Chinook wind
Encyclopedia
Chinook winds often called chinooks, commonly refers to foehn winds in the interior West of North America, where the Canadian Prairies
and Great Plains
meet various mountain ranges, although the original usage is in reference to wet, warm coastal winds in the Pacific Northwest
.
Chinook is claimed by popular mythology to mean "eater" but it is really the name of the people in the region where the usage was first derived. The reference to a wind or weather system, simply "a Chinook", originally meant a warming wind from the ocean into the interior regions of the Pacific Northwest
(the Chinook people lived near the ocean, along the lower Columbia River
). A strong Chinook can make snow one foot deep almost vanish in one day. The snow partly melts and partly evaporates in the dry wind. Chinook winds have been observed to raise winter temperature
, often from below -20 °C to as high as 10–20 °C (50–68 °F) for a few hours or days, then temperatures plummet to their base levels. The greatest recorded temperature change in 24 hours was caused by Chinook winds on January 15, 1972, in Loma, Montana
; the temperature rose from -48 °C.
The ch digraph
in Chinook is not pronounced as in the word "church" in some regions of the Pacific Coast, but as in French (i.e., shinook) in other regions of the Pacific Coast (e.g., Seattle) and on the prairies. This is because the French-speaking voyageurs of the fur companies brought the term from the mountains. The first syllable in Chicago
is pronounced similarly, also due to the original French speaking explorers.
in Canada, especially in a belt from Pincher Creek
and Crowsnest Pass
through Lethbridge
, which get 30 to 35 chinook days per year on average. Chinooks become less frequent further south in the United States, and are not as common north of Red Deer
. But they can and do occur annually as far north as High Level
in northwestern Alberta and Fort St. John
in northeastern British Columbia
, and as far south as Albuquerque, New Mexico
.
In southwestern Alberta, Chinook winds can gust in excess of hurricane force 120 or. On November 19, 1962, an especially powerful chinook in Lethbridge gusted to 171 km/h (106.3 mph).
In Pincher Creek, the temperature rose by 41 °C (74 °F), from -19 °C, in one hour in 1962 - trains have been known to be derailed by chinook winds there. During the winter, driving can be treacherous as the wind blows snow across roadways sometimes causing roads to vanish and snowdrifts to pile up higher than 1 metre. Empty semi trucks driving along Highway 3 and other routes in Southern Alberta have been blown over by the high gusts of wind caused by chinooks.
Calgary
also gets many chinooks - the Bow Valley in the Canadian Rockies
west of the city acts as a natural wind tunnel funneling the chinook winds.
In February 1992, Claresholm, Alberta
hit 24 °C (75.2 °F) - one of Canada's highest February temperatures.
at times. It is not unheard of for people in Lethbridge to complain of -20 °C temperatures while those in Cardston
, just 77 kilometres (47.8 mi) down the road, enjoy 10 °C (50 °F) temperatures. This clash of temperatures can remain stationary, or move back and forth, in the latter case causing such fluctuations as a warm morning, a bitterly cold afternoon, and a warm evening. A curtain of fog often accompanies the clash between warm to the west and cold to the east.
s caused by air rippling over the mountains due to orographic lifting. To those unfamiliar with the chinook, the chinook arch may look like a threatening storm cloud at times. However, they rarely produce rain or snow. They can also create stunning sunrises and sunsets.
The stunning colours seen in the chinook arch are quite common. Typically the colours will change throughout the day, starting with yellow, orange, red and pink shades in the morning as the sun comes up, grey shades in the mid day changing to pink/red colours, and then orange/yellow hues just before the sun sets.
). As a consequence of the different adiabatic rates of moist and dry air, the air on the leeward slopes becomes warmer than equivalent elevations on the windward slopes.
As moist winds from the Pacific (also called Chinooks) are forced to rise over the mountains, the moisture in the air is condensed and falls out as precipitation, while the air cools at the moist adiabatic rate of 5°C/1000 m (3.5°F/1000 ft). The dried air then descends on the leeward side of the mountains, warming at the dry adiabatic rate of 10°C/1000m (5.5°F/1000 ft).
The turbulence of the high winds also can prevent the normal nocturnal temperature inversion from forming on the lee side of the slope, allowing night-time temperatures to remain elevated.
Quite often when the Pacific Northwest
coast is being drenched by rain, the windward
side of the Rockies
is being hammered by snow (as the air loses its moisture), and the leeward
side of the Rockies in Alberta is basking in a foehn chinook. The three different weather conditions are all caused by the same flow of air, hence the confusion over the use of the name "Chinook wind".
Two common cloud patterns seen during this time are:
and/or
, now a hamlet, in southeastern Alberta, from where the wind seems to originate) can be fairly strong and cause bitter windchill
and blowing snow. The wind will eventually swing around to the southwest and the temperature rises sharply as the real chinook arrives.
, and is the original usage, being rooted in the lore of coastal tribes and brought to Alberta by the fur-traders. Such winds are extremely wet and warm and come from the southwest, and are also known as the Pineapple Express
since they are of tropical origin, roughly from the area of Hawaii. The air associated with a west coast Chinook is stable; this minimizes wind gusts and often keeps winds light in sheltered areas. In exposed areas, fresh gale
s are frequent during a Chinook, but strong gale or storm force winds are uncommon (most of the region's stormy winds come when a fast westerly jet stream lets air masses from temperate and subarctic latitudes clash).
When a Chinook comes in when an Arctic air mass is holding steady over the coast, the tropical dampness brought in suddenly cools, penetrating the frozen air and coming down in volumes of powder snow, sometimes to sea level
. Snowfalls and the cold spells that spawned them only last a few days during a Chinook: as the warm Chinooks blow from the southwest they push back east the cold Arctic air. The snow melts quickly and is gone within a week.
The effects on the Interior of B.C. when a Chinook is in effect are the reverse. In a rainy spell, most of the heavy moisture will be soaked out by the ramparts of mountains before the air mass reaches the Canyon
and the Thompson River
-Okanagan
area. The effects are similar to those of an Alberta Chinook, though not to the same extreme, in part because the Okanagan
is relatively warmer than the Prairies, and because of the additional number of precipitation-catching mountain ranges in between Kelowna
and Calgary. When the Chinook brings snow on the Coast
during a period of coastal cold, bright but chilly weather in the Interior will give way to a slushy melting of snow due to the warm spell more than because of rain.
The word is in common usage among local fishermen and people in communities along the British Columbia Coast
. The term is also used in the Puget Sound
area of Washington. It is important to note that Chinook is not pronounced as it is east of the Cascades – shinook – but is in the original coastal pronunciation tshinook.
An outflow wind is more or less the opposite of BC
/Pacific Northwest Chinook. These are called a squamish
in certain areas, rooted in the direction of such winds coming down out of Howe Sound
, home to the Skwxwu7mesh people, and in Alaska are called a williwaw
. They consist of cold air streams from the continental air mass pouring out of the interior plateau via certain river valleys and canyons penetrating the Coast Mountains
towards the coast.
and parts of the Pacific Northwest
, the word Chinook is often pronounced with a tshi-, as in Salish
. In Central Washington, Alberta, and the rest of Canada, it is pronounced with a shi-, as in French. This difference may be because it was the Métis
employees of the Hudson's Bay Company
, who were familiar with the Chinook people and country, brought the name east of the Cascades and Rockies
, along with their own ethnified pronunciation. Early records are clear that tshinook was the original pronunciation, before the word's transmission east of the Rockies.
tells of a girl named Chinook-Wind, who married Glacier
, and moved to his country, which was in the area of today's Birkenhead River
. She pined for her warm sea-home in the southwest, and sent a message to her people. They came to her in a vision in the form of snowflakes, and told her they were coming to get her. They came in great number and quarrelled with Glacier over her, but they overwhelmed him and she went home with them in the end.
While on the one hand this tale tells a tribal family-relations story, and family/tribal history as well, it also seems to be a parable of a typical weather pattern of a southwesterly wind at first bringing snow, then rain, and also of the melting of a glacier, namely the Place Glacier near Gates Lake at Birken
. Thus it also tells of a migration of people to the area, (or a war, depending on how the details of the legend might be read, with Chinook-Wind taking the part of Helen in a First Nations
parallel to the Trojan War
).
(where constant cold maintains dormancy all winter) are difficult in the Alberta chinook belt; examples include basswood
, some apple
, raspberry
and Saskatoon varieties, and Amur maple
. Trees in the Chinook affected areas of Alberta are known to be small, with much less growth than trees in areas not affected by Chinooks. This is once again caused by the 'off and on' dormancy throughout winter.
headaches suffered by the locals and are often called "chinook headaches". At least one study conducted by the department of clinical neurosciences at the University of Calgary
supports that belief. It is also popularly believed they can increase irritability
and sleeplessness
. In mid-winter over major centres such as Calgary, chinooks can often override cold air in the city, trapping the pollutants
in the cold air and causing inversion smog
. At such times it's possible for it to be cold at street level and much warmer at the tops of the skyscrapers and in higher terrain. In 1983, on the 45th floor (about 145m {460 feet} above the street) of the Petro-Canada Center, carpenters worked shirtless in plus twelve degrees Celsius, windy conditions (temperature reported to them by overhead crane operator) but were chagrined to find out the street temperature was still minus 20 Celsius as they left work at 3:30 that afternoon.
boasts as having the most extreme recorded temperature change in a 24-hour period. On January 15, 1972, the temperature rose from -54 °F, a 103 °F (58 °C) change in temperature; a dramatic example of the regional Chinook wind in action.
The Black Hills
of South Dakota
are home to the world's fastest recorded rise in temperature. On January 22, 1943, at about 7:30am MST, the temperature in Spearfish, South Dakota
was -4 °F. The chinook kicked in, and two minutes later the temperature was 45 °F (7.2 °C). The 49 °F (27 °C) rise in two minutes set a world record that is still on the books. By 9:00am, the temperature had risen to 54 °F (12.2 °C). Suddenly, the chinook died down and the temperature tumbled back to -4 °F. The 58 °F (32 °C) drop took only 27 minutes.
The aforementioned 107 mph (172.2 km/h) wind in Alberta and other local wind records west of the 100th meridian on the Great Plains of the United States and Canada, as well as instances of the record high and low temperature for a given day of the year being set on the same date are largely the result of these winds.
On rare occasions chinook winds generated on the eastern slope of the Rocky Mountains have reached or passed the Mississippi River.
region. Montana
in particular has a significant amount of Chinook winds across much of the state during the winter months, but particularly coming off of the Rocky Mountain Front
in the north and west-central areas of the state.
One such wind occurs in the Cook Inlet
region in Alaska as air moves over the Chugach Mountains
between Prince William Sound
and Portage Glacier
. Anchorage
residents often believe that the warm winds which melt snow and leave their streets slushy and muddy are a midwinter gift from Hawaii, following a common mistake that the warm winds come from the same place as the similar winds near the coasts in southern British Columbia
, Washington, and Oregon
.
Chinooks also occur in Colorado
, especially near Denver, where winds blowing over the Rocky Mountain Front Range
have raised winter temperatures from below freezing to around 50 °F (10 °C) in just a few hours. There are also Chinook winds in and around other cities in the Rocky Mountain states, including Billings
, Salt Lake City
and Albuquerque
.
Canadian Prairies
The Canadian Prairies is a region of Canada, specifically in western Canada, which may correspond to several different definitions, natural or political. Notably, the Prairie provinces or simply the Prairies comprise the provinces of Alberta, Saskatchewan, and Manitoba, as they are largely covered...
and Great Plains
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
meet various mountain ranges, although the original usage is in reference to wet, warm coastal winds in the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...
.
Chinook is claimed by popular mythology to mean "eater" but it is really the name of the people in the region where the usage was first derived. The reference to a wind or weather system, simply "a Chinook", originally meant a warming wind from the ocean into the interior regions of the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...
(the Chinook people lived near the ocean, along the lower Columbia River
Columbia River
The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada, flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state...
). A strong Chinook can make snow one foot deep almost vanish in one day. The snow partly melts and partly evaporates in the dry wind. Chinook winds have been observed to raise winter temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
, often from below -20 °C to as high as 10–20 °C (50–68 °F) for a few hours or days, then temperatures plummet to their base levels. The greatest recorded temperature change in 24 hours was caused by Chinook winds on January 15, 1972, in Loma, Montana
Loma, Montana
Loma is a census-designated place in Chouteau County, Montana, United States. The population was 92 at the 2000 census.-Geography and climate:Loma is located at ....
; the temperature rose from -48 °C.
The ch digraph
Digraph (orthography)
A digraph or digram is a pair of characters used to write one phoneme or a sequence of phonemes that does not correspond to the normal values of the two characters combined...
in Chinook is not pronounced as in the word "church" in some regions of the Pacific Coast, but as in French (i.e., shinook) in other regions of the Pacific Coast (e.g., Seattle) and on the prairies. This is because the French-speaking voyageurs of the fur companies brought the term from the mountains. The first syllable in Chicago
History of Chicago
The history of Chicago, Illinois, has played an important role in the history of the United States. Americans founded the city in 1832. The Chicago area's recorded history begins with the arrival of French explorers, missionaries and fur traders in the late 17th century...
is pronounced similarly, also due to the original French speaking explorers.
In Canada
Chinooks are most prevalent over southern AlbertaAlberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
in Canada, especially in a belt from Pincher Creek
Pincher Creek, Alberta
Pincher Creek is a town in the southwest of Alberta, Canada. It is located immediately east of the Canadian Rockies in the centre of ranching country, north of Waterton Lakes National Park.The town's mayor is Ernie Olsen.- History :...
and Crowsnest Pass
Crowsnest Pass, Alberta
The Municipality of Crowsnest Pass is a specialized municipality located in the Crowsnest Pass of the Rocky Mountains in southwest Alberta, Canada. The municipality formed as a result of the amalgamation of five municipalities – the Village of Bellevue, the Town of Blairmore, Town of Coleman, the...
through Lethbridge
Lethbridge
Lethbridge is a city in the province of Alberta, Canada, and the largest city in southern Alberta. It is Alberta's fourth-largest city by population after Calgary, Edmonton and Red Deer, and the third-largest by area after Calgary and Edmonton. The nearby Canadian Rockies contribute to the city's...
, which get 30 to 35 chinook days per year on average. Chinooks become less frequent further south in the United States, and are not as common north of Red Deer
Red Deer, Alberta
Red Deer is a city in Central Alberta, Canada. It is located near the midpoint of the Calgary-Edmonton Corridor and is surrounded by Red Deer County. It is Alberta's third-most-populous city – after Calgary and Edmonton. The city is located in aspen parkland, a region of rolling hills...
. But they can and do occur annually as far north as High Level
High Level, Alberta
- Demographics :According to the 2006 census, High Level had a:*population of 3,887 living in 1,519 dwellings, a 12.9% increase from 2001;*land area of ; and*population density of .- Economy :...
in northwestern Alberta and Fort St. John
Fort St. John, British Columbia
The City of Fort St. John is a city in northeastern British Columbia, Canada. A member municipality of the Peace River Regional District, the city covers an area of about 22 km² with 22,000 residents . Located at Mile 47, it is one of the largest cities along the Alaska Highway. Originally...
in northeastern British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
, and as far south as Albuquerque, New Mexico
Albuquerque, New Mexico
Albuquerque is the largest city in the state of New Mexico, United States. It is the county seat of Bernalillo County and is situated in the central part of the state, straddling the Rio Grande. The city population was 545,852 as of the 2010 Census and ranks as the 32nd-largest city in the U.S. As...
.
In southwestern Alberta, Chinook winds can gust in excess of hurricane force 120 or. On November 19, 1962, an especially powerful chinook in Lethbridge gusted to 171 km/h (106.3 mph).
In Pincher Creek, the temperature rose by 41 °C (74 °F), from -19 °C, in one hour in 1962 - trains have been known to be derailed by chinook winds there. During the winter, driving can be treacherous as the wind blows snow across roadways sometimes causing roads to vanish and snowdrifts to pile up higher than 1 metre. Empty semi trucks driving along Highway 3 and other routes in Southern Alberta have been blown over by the high gusts of wind caused by chinooks.
Calgary
Calgary
Calgary is a city in the Province of Alberta, Canada. It is located in the south of the province, in an area of foothills and prairie, approximately east of the front ranges of the Canadian Rockies...
also gets many chinooks - the Bow Valley in the Canadian Rockies
Canadian Rockies
The Canadian Rockies comprise the Canadian segment of the North American Rocky Mountains range. They are the eastern part of the Canadian Cordillera, extending from the Interior Plains of Alberta to the Rocky Mountain Trench of British Columbia. The southern end borders Idaho and Montana of the USA...
west of the city acts as a natural wind tunnel funneling the chinook winds.
In February 1992, Claresholm, Alberta
Claresholm, Alberta
Claresholm is a town located within southern Alberta, Canada. It is located on Highway 2, approximately northwest of the City of Lethbridge and south of the City of Calgary. The town is the seat of the Municipal District of Willow Creek No...
hit 24 °C (75.2 °F) - one of Canada's highest February temperatures.
Chinooks versus the Arctic air mass
The chinook can seem to do battle with the Arctic air massAir mass
In meteorology, an air mass is a volume of air defined by its temperature and water vapor content. Air masses cover many hundreds or thousands of square miles, and adopt the characteristics of the surface below them. They are classified according to latitude and their continental or maritime...
at times. It is not unheard of for people in Lethbridge to complain of -20 °C temperatures while those in Cardston
Cardston, Alberta
-Demographics:The population of the Town of Cardston according to its 2007 municipal census is 3,578.In 2006, it had a population of 3,452 living in 1,234 dwellings, a 0.7% decrease from 2001...
, just 77 kilometres (47.8 mi) down the road, enjoy 10 °C (50 °F) temperatures. This clash of temperatures can remain stationary, or move back and forth, in the latter case causing such fluctuations as a warm morning, a bitterly cold afternoon, and a warm evening. A curtain of fog often accompanies the clash between warm to the west and cold to the east.
Chinook arch
One of the most striking features of the chinook is the chinook arch, which is a band of stationary stratus cloudStratus cloud
A stratus cloud is a cloud belonging to a class characterized by horizontal layering with a uniform base, as opposed to convective clouds that are as tall or taller than wide . More specifically, the term stratus is used to describe flat, hazy, featureless clouds of low altitude varying in color...
s caused by air rippling over the mountains due to orographic lifting. To those unfamiliar with the chinook, the chinook arch may look like a threatening storm cloud at times. However, they rarely produce rain or snow. They can also create stunning sunrises and sunsets.
The stunning colours seen in the chinook arch are quite common. Typically the colours will change throughout the day, starting with yellow, orange, red and pink shades in the morning as the sun comes up, grey shades in the mid day changing to pink/red colours, and then orange/yellow hues just before the sun sets.
How chinooks occur
The Chinook is a foehn wind, a rain shadow wind which results from the subsequent adiabatic warming of air which has dropped most of its moisture on windward slopes (orographic liftOrographic lift
Orographic lift occurs when an air mass is forced from a low elevation to a higher elevation as it moves over rising terrain. As the air mass gains altitude it quickly cools down adiabatically, which can raise the relative humidity to 100% and create clouds and, under the right conditions,...
). As a consequence of the different adiabatic rates of moist and dry air, the air on the leeward slopes becomes warmer than equivalent elevations on the windward slopes.
As moist winds from the Pacific (also called Chinooks) are forced to rise over the mountains, the moisture in the air is condensed and falls out as precipitation, while the air cools at the moist adiabatic rate of 5°C/1000 m (3.5°F/1000 ft). The dried air then descends on the leeward side of the mountains, warming at the dry adiabatic rate of 10°C/1000m (5.5°F/1000 ft).
The turbulence of the high winds also can prevent the normal nocturnal temperature inversion from forming on the lee side of the slope, allowing night-time temperatures to remain elevated.
Quite often when the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...
coast is being drenched by rain, the windward
Windward and leeward
Windward is the direction upwind from the point of reference. Leeward is the direction downwind from the point of reference. The side of a ship that is towards the leeward is its lee side. If the vessel is heeling under the pressure of the wind, this will be the "lower side"...
side of the Rockies
Canadian Rockies
The Canadian Rockies comprise the Canadian segment of the North American Rocky Mountains range. They are the eastern part of the Canadian Cordillera, extending from the Interior Plains of Alberta to the Rocky Mountain Trench of British Columbia. The southern end borders Idaho and Montana of the USA...
is being hammered by snow (as the air loses its moisture), and the leeward
Windward and leeward
Windward is the direction upwind from the point of reference. Leeward is the direction downwind from the point of reference. The side of a ship that is towards the leeward is its lee side. If the vessel is heeling under the pressure of the wind, this will be the "lower side"...
side of the Rockies in Alberta is basking in a foehn chinook. The three different weather conditions are all caused by the same flow of air, hence the confusion over the use of the name "Chinook wind".
Two common cloud patterns seen during this time are:
- A chinook arch overhead
and/or
- A bank of clouds (also referred to as a cloud wall) obscuring the mountains to the west. It appears to be an approaching storm, but does not advance any further east.
The Manyberries chinook
Often, a chinook is preceded by a "Manyberries chinook" during the end of a cold spell. This southeast wind (named for the small village ManyberriesManyberries, Alberta
- References :...
, now a hamlet, in southeastern Alberta, from where the wind seems to originate) can be fairly strong and cause bitter windchill
Wind chill
Wind chill is the felt air temperature on exposed skin due to wind. The wind chill temperature is always lower than the air temperature, and the windchill is undefined at the higher temps...
and blowing snow. The wind will eventually swing around to the southwest and the temperature rises sharply as the real chinook arrives.
The Chinook in the Pacific Northwest
The term Chinook Wind is also used in British ColumbiaBritish Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
, and is the original usage, being rooted in the lore of coastal tribes and brought to Alberta by the fur-traders. Such winds are extremely wet and warm and come from the southwest, and are also known as the Pineapple Express
Pineapple Express
Pineapple Express is a non-technical term for a meteorological phenomenon characterized by a strong and persistent flow of atmospheric moisture and associated heavy rainfall from the waters adjacent to the Hawaiian Islands and extending to any location along the Pacific coast of North America...
since they are of tropical origin, roughly from the area of Hawaii. The air associated with a west coast Chinook is stable; this minimizes wind gusts and often keeps winds light in sheltered areas. In exposed areas, fresh gale
Gale
A gale is a very strong wind. There are conflicting definitions of how strong a wind must be to be considered a gale. The U.S. government's National Weather Service defines a gale as 34–47 knots of sustained surface winds. Forecasters typically issue gale warnings when winds of this strength are...
s are frequent during a Chinook, but strong gale or storm force winds are uncommon (most of the region's stormy winds come when a fast westerly jet stream lets air masses from temperate and subarctic latitudes clash).
When a Chinook comes in when an Arctic air mass is holding steady over the coast, the tropical dampness brought in suddenly cools, penetrating the frozen air and coming down in volumes of powder snow, sometimes to sea level
Sea level
Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...
. Snowfalls and the cold spells that spawned them only last a few days during a Chinook: as the warm Chinooks blow from the southwest they push back east the cold Arctic air. The snow melts quickly and is gone within a week.
The effects on the Interior of B.C. when a Chinook is in effect are the reverse. In a rainy spell, most of the heavy moisture will be soaked out by the ramparts of mountains before the air mass reaches the Canyon
Fraser Canyon
The Fraser Canyon is an 84 km landform of the Fraser River where it descends rapidly through narrow rock gorges in the Coast Mountains en route from the Interior Plateau of British Columbia to the Fraser Valley...
and the Thompson River
Thompson River
The Thompson River is the largest tributary of the Fraser River, flowing through the south-central portion of British Columbia, Canada. The Thompson River has two main branches called the South Thompson and the North Thompson...
-Okanagan
Okanagan
The Okanagan , also known as the Okanagan Valley and sometimes as Okanagan Country is a region located in the Canadian province of British Columbia defined by the basin of Okanagan Lake and the Canadian portion of the Okanagan River. As of 2009, the region's population is approximately 350,927. The...
area. The effects are similar to those of an Alberta Chinook, though not to the same extreme, in part because the Okanagan
Okanagan
The Okanagan , also known as the Okanagan Valley and sometimes as Okanagan Country is a region located in the Canadian province of British Columbia defined by the basin of Okanagan Lake and the Canadian portion of the Okanagan River. As of 2009, the region's population is approximately 350,927. The...
is relatively warmer than the Prairies, and because of the additional number of precipitation-catching mountain ranges in between Kelowna
Kelowna
Kelowna is a city on Okanagan Lake in the Okanagan Valley, in the southern interior of British Columbia, Canada. Its name derives from a Okanagan language term for "grizzly bear"...
and Calgary. When the Chinook brings snow on the Coast
British Columbia Coast
The British Columbia Coast or BC Coast is Canada's western continental coastline on the Pacific Ocean. The usage is synonymous with the term West Coast of Canada....
during a period of coastal cold, bright but chilly weather in the Interior will give way to a slushy melting of snow due to the warm spell more than because of rain.
The word is in common usage among local fishermen and people in communities along the British Columbia Coast
British Columbia Coast
The British Columbia Coast or BC Coast is Canada's western continental coastline on the Pacific Ocean. The usage is synonymous with the term West Coast of Canada....
. The term is also used in the Puget Sound
Puget Sound
Puget Sound is a sound in the U.S. state of Washington. It is a complex estuarine system of interconnected marine waterways and basins, with one major and one minor connection to the Strait of Juan de Fuca and the Pacific Ocean — Admiralty Inlet being the major connection and...
area of Washington. It is important to note that Chinook is not pronounced as it is east of the Cascades – shinook – but is in the original coastal pronunciation tshinook.
An outflow wind is more or less the opposite of BC
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
/Pacific Northwest Chinook. These are called a squamish
Squamish (wind)
A squamish is a strong and often violent wind occurring in many of the fjords, inlets and valleys of British Columbia. Squamishes occur in those fjords oriented in a northeast-southwest or east-west direction where cold polar air can be funneled westward, the opposite of how the wind generally...
in certain areas, rooted in the direction of such winds coming down out of Howe Sound
Howe Sound
Howe Sound is a roughly triangular sound, actually a network of fjords situated immediately northwest of Vancouver.-Geography:Howe Sound's mouth at the Strait of Georgia is situated between West Vancouver and the Sunshine Coast. The sound is triangular shaped, open on its southeast towards the...
, home to the Skwxwu7mesh people, and in Alaska are called a williwaw
Williwaw
In meteorology, a williwaw is a sudden blast of wind descending from a mountainous coast to the sea. The word is of unknown origin, but was earliest used by British seamen in the 19th century...
. They consist of cold air streams from the continental air mass pouring out of the interior plateau via certain river valleys and canyons penetrating the Coast Mountains
Coast Mountains
The Coast Mountains are a major mountain range, in the Pacific Coast Ranges, of western North America, extending from southwestern Yukon through the Alaska Panhandle and virtually all of the Coast of British Columbia. They are so-named because of their proximity to the sea coast, and are often...
towards the coast.
Pronunciation in BC and the Pacific Northwest
In British ColumbiaBritish Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
and parts of the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...
, the word Chinook is often pronounced with a tshi-, as in Salish
Salishan languages
The Salishan languages are a group of languages of the Pacific Northwest...
. In Central Washington, Alberta, and the rest of Canada, it is pronounced with a shi-, as in French. This difference may be because it was the Métis
Métis people (Canada)
The Métis are one of the Aboriginal peoples in Canada who trace their descent to mixed First Nations parentage. The term was historically a catch-all describing the offspring of any such union, but within generations the culture syncretised into what is today a distinct aboriginal group, with...
employees of the Hudson's Bay Company
Hudson's Bay Company
The Hudson's Bay Company , abbreviated HBC, or "The Bay" is the oldest commercial corporation in North America and one of the oldest in the world. A fur trading business for much of its existence, today Hudson's Bay Company owns and operates retail stores throughout Canada...
, who were familiar with the Chinook people and country, brought the name east of the Cascades and Rockies
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
, along with their own ethnified pronunciation. Early records are clear that tshinook was the original pronunciation, before the word's transmission east of the Rockies.
First nations myth of B.C.
Native legend of the Lil'wat subgroup of the St'at'imcSt'at'imc
The St'át'imc are an Interior Salish people located in the southern Coast Mountains and Fraser Canyon region of the Interior of the Canadian province of British Columbia.St'át'imc culture displayed many features typical of Northwest Coast peoples: the...
tells of a girl named Chinook-Wind, who married Glacier
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
, and moved to his country, which was in the area of today's Birkenhead River
Birkenhead River
The Birkenhead River, formerly known as the Portage River, the Pole River and the Mosquito River, is a major tributary of the Lillooet River, which via Harrison Lake and the Harrison River is one of the major tributaries of the lower Fraser River...
. She pined for her warm sea-home in the southwest, and sent a message to her people. They came to her in a vision in the form of snowflakes, and told her they were coming to get her. They came in great number and quarrelled with Glacier over her, but they overwhelmed him and she went home with them in the end.
While on the one hand this tale tells a tribal family-relations story, and family/tribal history as well, it also seems to be a parable of a typical weather pattern of a southwesterly wind at first bringing snow, then rain, and also of the melting of a glacier, namely the Place Glacier near Gates Lake at Birken
Birken, British Columbia
Birken is an unincorporated community, located at Birken Lake in the Gates Valley of the Lillooet Country in the Southern Interior of British Columbia, Canada, approximately midway in the route known as the Long Portage or Pemberton Pass, which connects the Pemberton Valley to the Fraser Canyon via...
. Thus it also tells of a migration of people to the area, (or a war, depending on how the details of the legend might be read, with Chinook-Wind taking the part of Helen in a First Nations
First Nations
First Nations is a term that collectively refers to various Aboriginal peoples in Canada who are neither Inuit nor Métis. There are currently over 630 recognised First Nations governments or bands spread across Canada, roughly half of which are in the provinces of Ontario and British Columbia. The...
parallel to the Trojan War
Trojan War
In Greek mythology, the Trojan War was waged against the city of Troy by the Achaeans after Paris of Troy took Helen from her husband Menelaus, the king of Sparta. The war is among the most important events in Greek mythology and was narrated in many works of Greek literature, including the Iliad...
).
Gardening
The frequent midwinter thaws in Great Plains chinook country are more of a bane than a blessing to gardeners. Plants can be visibly brought out of dormancy by persistent chinook winds, or have their hardiness reduced even if they appear to be remaining dormant. In either case, they become vulnerable to later cold waves. Many plants which do well at WinnipegWinnipeg
Winnipeg is the capital and largest city of Manitoba, Canada, and is the primary municipality of the Winnipeg Capital Region, with more than half of Manitoba's population. It is located near the longitudinal centre of North America, at the confluence of the Red and Assiniboine Rivers .The name...
(where constant cold maintains dormancy all winter) are difficult in the Alberta chinook belt; examples include basswood
Tilia americana
Tilia americana is a species of Tilia native to eastern North America, from southeast Manitoba east to New Brunswick, southwest to northeast Texas, and southeast to South Carolina, and west along the Niobrara River to Cherry County, Nebraska...
, some apple
Apple
The apple is the pomaceous fruit of the apple tree, species Malus domestica in the rose family . It is one of the most widely cultivated tree fruits, and the most widely known of the many members of genus Malus that are used by humans. Apple grow on small, deciduous trees that blossom in the spring...
, raspberry
Raspberry
The raspberry or hindberry is the edible fruit of a multitude of plant species in the genus Rubus, most of which are in the subgenus Idaeobatus; the name also applies to these plants themselves...
and Saskatoon varieties, and Amur maple
Amur Maple
Acer ginnala is a plant species with woody stems native to northeastern Asia from easternmost Mongolia east to Korea and Japan, and north to southeastern Siberia in the Amur River valley...
. Trees in the Chinook affected areas of Alberta are known to be small, with much less growth than trees in areas not affected by Chinooks. This is once again caused by the 'off and on' dormancy throughout winter.
Health
It is said that chinook winds can cause a sharp increase in the number of migraineMigraine
Migraine is a chronic neurological disorder characterized by moderate to severe headaches, and nausea...
headaches suffered by the locals and are often called "chinook headaches". At least one study conducted by the department of clinical neurosciences at the University of Calgary
University of Calgary
The University of Calgary is a public research university located in Calgary, Alberta, Canada. Founded in 1966 the U of C is composed of 14 faculties and more than 85 research institutes and centres.More than 25,000 undergraduate and 5,500 graduate students are currently...
supports that belief. It is also popularly believed they can increase irritability
Irritability
Irritability is an excessive response to stimuli. The term is used for both the physiological reaction to stimuli and for the pathological, abnormal or excessive sensitivity to stimuli; It is usually used to refer to anger or frustration....
and sleeplessness
Insomnia
Insomnia is most often defined by an individual's report of sleeping difficulties. While the term is sometimes used in sleep literature to describe a disorder demonstrated by polysomnographic evidence of disturbed sleep, insomnia is often defined as a positive response to either of two questions:...
. In mid-winter over major centres such as Calgary, chinooks can often override cold air in the city, trapping the pollutants
Smog
Smog is a type of air pollution; the word "smog" is a portmanteau of smoke and fog. Modern smog is a type of air pollution derived from vehicular emission from internal combustion engines and industrial fumes that react in the atmosphere with sunlight to form secondary pollutants that also combine...
in the cold air and causing inversion smog
Smog
Smog is a type of air pollution; the word "smog" is a portmanteau of smoke and fog. Modern smog is a type of air pollution derived from vehicular emission from internal combustion engines and industrial fumes that react in the atmosphere with sunlight to form secondary pollutants that also combine...
. At such times it's possible for it to be cold at street level and much warmer at the tops of the skyscrapers and in higher terrain. In 1983, on the 45th floor (about 145m {460 feet} above the street) of the Petro-Canada Center, carpenters worked shirtless in plus twelve degrees Celsius, windy conditions (temperature reported to them by overhead crane operator) but were chagrined to find out the street temperature was still minus 20 Celsius as they left work at 3:30 that afternoon.
Folklore
There are three especially famous chinook folk tales that most people in southern Alberta probably know in some form from childhood stories.- A man rode his horse to church, only to find just the steeple sticking out of the snow. So, he tied his horse to the steeple with the other horses, and went down the snow tunnel to attend services. When everybody emerged from the church, they found that a chinook had melted all of the snow, and their horses were now all dangling from the church steeple.
- A man was riding his sleigh to town when a chinook overcame him. He kept pace with the wind, and while the horses were running belly deep in snow, the sleigh rails were running in mud up to the buckboard. The cow that was tied behind was kicking up dust.
- A man and his wife were out during a chinook. The wife was heavily dressed and the man was wearing summer clothes. When the couple had returned home, the man had frostbite, and the woman had heatstroke.
Records
Loma, MontanaLoma, Montana
Loma is a census-designated place in Chouteau County, Montana, United States. The population was 92 at the 2000 census.-Geography and climate:Loma is located at ....
boasts as having the most extreme recorded temperature change in a 24-hour period. On January 15, 1972, the temperature rose from -54 °F, a 103 °F (58 °C) change in temperature; a dramatic example of the regional Chinook wind in action.
The Black Hills
Black Hills
The Black Hills are a small, isolated mountain range rising from the Great Plains of North America in western South Dakota and extending into Wyoming, USA. Set off from the main body of the Rocky Mountains, the region is something of a geological anomaly—accurately described as an "island of...
of South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
are home to the world's fastest recorded rise in temperature. On January 22, 1943, at about 7:30am MST, the temperature in Spearfish, South Dakota
Spearfish, South Dakota
Spearfish is a city in Lawrence County, South Dakota,United States. The population was 10,494 at the 2010 census.- History :Prior to the Black Hills Gold Rush of 1876, the area was used by Native Americans who would spear fish in the creek...
was -4 °F. The chinook kicked in, and two minutes later the temperature was 45 °F (7.2 °C). The 49 °F (27 °C) rise in two minutes set a world record that is still on the books. By 9:00am, the temperature had risen to 54 °F (12.2 °C). Suddenly, the chinook died down and the temperature tumbled back to -4 °F. The 58 °F (32 °C) drop took only 27 minutes.
The aforementioned 107 mph (172.2 km/h) wind in Alberta and other local wind records west of the 100th meridian on the Great Plains of the United States and Canada, as well as instances of the record high and low temperature for a given day of the year being set on the same date are largely the result of these winds.
On rare occasions chinook winds generated on the eastern slope of the Rocky Mountains have reached or passed the Mississippi River.
Chinook and foehn wind in the United States
Chinooks are generally called foehn winds by meteorologists and climatologists, and, regardless of name, can occur in most places on the leeward side of a nearby mountain range. They are called "chinook winds" throughout most of western North America, particularly the Rocky MountainRocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
region. Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
in particular has a significant amount of Chinook winds across much of the state during the winter months, but particularly coming off of the Rocky Mountain Front
Rocky Mountain Front
The Rocky Mountain Front is an area extending over 100 miles from the central regions of the U.S. state of Montana to southern Alberta, Canada. Here, the Rocky Mountains meet the Great Plains and Canadian Prairie in an abrupt elevation rise of between 4,000 to 5,000 feet...
in the north and west-central areas of the state.
One such wind occurs in the Cook Inlet
Cook Inlet
Cook Inlet stretches from the Gulf of Alaska to Anchorage in south-central Alaska. Cook Inlet branches into the Knik Arm and Turnagain Arm at its northern end, almost surrounding Anchorage....
region in Alaska as air moves over the Chugach Mountains
Chugach Mountains
The Chugach Mountains of southern Alaska are the northernmost of the several mountain ranges that make up the Pacific Coast Ranges of the western edge of North America. The range is about 500 km long, running generally east-west. Its highest point is Mount Marcus Baker, at , but most of its...
between Prince William Sound
Prince William Sound
Prince William Sound is a sound off the Gulf of Alaska on the south coast of the U.S. state of Alaska. It is located on the east side of the Kenai Peninsula. Its largest port is Valdez, at the southern terminus of the Trans-Alaska Pipeline System...
and Portage Glacier
Portage Glacier
Portage Glacier is a glacier on the Kenai Peninsula of the U.S. state of Alaskaand is included within the Chugach National Forest. It is located south of Portage Lake and 6 km west of Whittier....
. Anchorage
Anchorage, Alaska
Anchorage is a unified home rule municipality in the southcentral part of the U.S. state of Alaska. It is the northernmost major city in the United States...
residents often believe that the warm winds which melt snow and leave their streets slushy and muddy are a midwinter gift from Hawaii, following a common mistake that the warm winds come from the same place as the similar winds near the coasts in southern British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
, Washington, and Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
.
Chinooks also occur in Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
, especially near Denver, where winds blowing over the Rocky Mountain Front Range
Front Range
The Front Range is a mountain range of the Southern Rocky Mountains of North America located in the north-central portion of the U.S. State of Colorado and southeastern portion of the U.S. State of Wyoming. It is the first mountain range encountered moving west along the 40th parallel north across...
have raised winter temperatures from below freezing to around 50 °F (10 °C) in just a few hours. There are also Chinook winds in and around other cities in the Rocky Mountain states, including Billings
Billings, Montana
Billings is the largest city in the U.S. state of Montana, and is the principal city of the Billings Metropolitan Area, the largest metropolitan area in over...
, Salt Lake City
Salt Lake City, Utah
Salt Lake City is the capital and the most populous city of the U.S. state of Utah. The name of the city is often shortened to Salt Lake or SLC. With a population of 186,440 as of the 2010 Census, the city lies in the Salt Lake City metropolitan area, which has a total population of 1,124,197...
and Albuquerque
Albuquerque, New Mexico
Albuquerque is the largest city in the state of New Mexico, United States. It is the county seat of Bernalillo County and is situated in the central part of the state, straddling the Rio Grande. The city population was 545,852 as of the 2010 Census and ranks as the 32nd-largest city in the U.S. As...
.
See also
- Diablo windDiablo windDiablo wind is a name that has been occasionally used for the hot, dry offshore wind from the northeast that typically occurs in the San Francisco Bay Area of Northern California during the spring and fall. The same wind pattern also affects other parts of California's coastal ranges...
- Foehn wind
- Katabatic winds
- Nor'west archNor'west archThe Nor'west arch is a weather pattern peculiar to the east coast of New Zealand's South Island. For this reason, it is also often referred to as the Canterbury arch. It is shown in an apparent arch of high white cloud in an otherwise clear blue sky over the Southern Alps, and is accompanied by a...
- Santa Ana windSanta Ana windThe Santa Ana winds are strong, extremely dry offshore winds that characteristically sweep through Southern California and northern Baja California in late fall and winter. They can range from hot to cold, depending on the prevailing temperatures in the source regions, the Great Basin and upper...
- Sundowner (wind)Sundowner (wind)A sundowner is an offshore northerly Foehn wind in Santa Barbara, California. It occurs when a region of high pressure is directly north of the area, whose coast trends east–west. This contrasts with the more typical onshore flow...
- Loo (wind)Loo (wind)The Loo is a strong, hot and dry summer afternoon wind from the west which blows over the western Indo-Gangetic Plain region of North India and Pakistan. It is especially strong in the months of May and June...