Halloween Blizzard
Encyclopedia
The Halloween Blizzard was a period of heavy snowfall and ice
accumulation that affected parts of the Upper Midwest
of the United States
, from October 31 to November 3, 1991. Over the last week of October 1991 a large storm system over the Atlantic Ocean (1991 Perfect Storm) blocked most of the weather patterns over the eastern half of the United States, and in turn moisture from the Gulf of Mexico
was funneled straight northward over the affected region. By the time the precipitation stopped falling many cities in the eastern half of Minnesota and northwestern Wisconsin had witnessed record early-season snowfall accumulations, while parts of southern Minnesota and northern Iowa were crippled by a large ice storm. Arctic
air that was pulled southward behind the storm had combined with the heavy snow pack to produce many record low temperatures. Between the blizzard and the ice storm 22 people were killed and over 100 were injured.
that pushed south and east through the central United States several days prior. On October 28 temperatures to the east of the cold front were above normal. High temperatures reached into the 70s from the middle Mississippi River Valley south into northern Texas
, and into the 80s across much of central and southern Texas. Meanwhile, high temperatures did not reach 20 degrees across most of Montana
and Wyoming
.
The contrast between the two air masses was stark, and by the morning of October 29 the cold front was about halfway through Texas. At 6 AM CST, the temperature in the western Texas city of Amarillo
had dropped to 22 degrees with a strong northerly breeze. Farther east in Texas the temperature was 64 in Dallas – a 42-degree temperature difference over about 300 miles. In the northern United States, morning lows were much colder. Temperatures were in the single digits across Montana and Wyoming and in the teens North Dakota
and South Dakota
.
By October 30, the cold front had pushed east to the Texas shoreline with the Gulf of Mexico
, and stalled in that location. As an upper-level shortwave trough
approached the Southern Plains
, it aided the development of an area of surface low pressure along the sharp temperature gradient near the Texas Gulf Coast. The development of low-pressure systems along coastal fronts in this fashion is relatively common in the cool season along the Texas Gulf Coast and along the Atlantic Seaboard near the Gulf Stream
current.
From October 30 - 31, this low pressure system slowly became better organized over Texas, before it ejected north over the Mississippi River Valley. This meridonal trajectory
of a low pressure track (almost due north from the western Gulf) is climatologically favorable to produce very heavy snowfall in the winter months because it allows copious amounts of moisture to flow north where it can interact with colder air. Cooler readings lingered at the very end of October across the Upper Midwest
, and a re-enforcing pool of Arctic air was just beginning to push southeast through the western Canadian Provinces.
On November 1, the surface low pressure moved north from western Illinois
into the Upper Peninsula of Michigan
and the minimum pressure fell about 24 millibars in 24 hours, indicative of rapid deepening and strengthening of the cyclone. The low pressure eventually became occluded
, weakened, and then continued to dissipate as it pushed east across northern Ontario
in subsequent days.
. During Halloween day the precipitation spread to the north where it fell mostly as rapidly accumulating snow. The snow continued to develop northward, eventually spreading into the Minnesota Arrowhead
. Eventually all of the precipitation changed over to snow, and in some areas it would continue falling until November 3.
had already recorded 8.2 in (20.8 cm) of snow. This not only set a record for the largest amount of snow on that date, but also for the most snow ever recorded in the Twin Cities during the month of October. As the storm system pushed its way northward, more communities in eastern Minnesota and northwestern Wisconsin began to experience similar conditions.
Over the next two days the snow continued to fall, leading to additional snowfall of one to two feet (30 cm to 60 cm). By the time the snow ended on November 3 the storm had dropped 36.9 in (93.7 cm) on Duluth
, the largest single snow storm total in Minnesota
history at that time. The Twin Cities received 28.4 in (72.1 cm), setting a single-storm record for the metropolitan area. In all, at least one foot (30 cm) of snow fell in a swath approximately 100 mi (160 km) wide from south central Minnesota, northeastward into northwestern Wisconsin and into the Minnesota Arrowhead
. A more narrow band of 2+ ft (60+ cm) of snow fell from the Twin Cities to Duluth and northward.
corridor did not see as much snow, but instead saw a major ice storm
. Though the precipitation started out as snow in these areas, it changed over to ice during the day on October 31 continued falling over the next day. Ice accumulations as high as 2–3 in (6 cm–9 cm) were recorded in these areas before the precipitation changed to snow. Up to 10 in (25.4 cm) of snow proceeded to fall on top of ice accumulations from the previous day, making travel even more treacherous. Up to 1 inch of ice accumulation was reported as far south as Omaha, Nebraska
.
Many roads were closed both from the snow and ice, including long stretches of I-90, I-35 and I-29 in Iowa, Minnesota and South Dakota. Highway snow removal was hindered by record cold temperatures that followed the storm and transportation was hampered for many days. Nine hundred schools and business were closed in Minnesota alone. Twenty two people died in this storm, twenty in Minnesota and two on the Mississippi River near La Crosse.
and Eau Claire, Wisconsin
. Following the storm Arctic air poured southward from Canada to produce many record low temperatures in these same areas. Bismarck, North Dakota
, sank to −10 °F on October 31, breaking their previous record low of 6 °F by 16 degrees. Record snow and cold was recorded as far south as Nebraska and Colorado. The Arctic air also spread over Chicago, recording a low of 11 on November 4.
Four weeks later on November 29–30, another large storm system dropped as much as 18 inches of snow over these same areas. These two storms combined to set a single-month record for most snowfall in the Twin Cities and Duluth.
! colspan="3" | Records tied or broken during the Halloween Blizzard>
Event 1991 record
Old Record (1891–1990)
Duluth, Minnesota
Most snow on October 31
4.2 in (10.6 cm)
m
Most snow on November 1
24.1 in (61.2 cm)
m
Most single storm snow total
36.9 in (93.7 cm)
m
Most snowfall in any month
50.1 in (127.3 cm) (Nov, 1991)
46.8 in (118.9 cm) (Jan, 1969)
Eau Claire, Wisconsin
Most snow on November 1
3.1 in (7.9 cm)
m
International Falls, Minnesota
Most snow on November 1
11.6 in (29.5 cm )
2.7 in (1974)
La Crosse, Wisconsin
Most snow on November 1
9.2 in (23.4 cm)
m
Omaha, Nebraska
Most snow on October 31
5.7 in
St. Cloud, Minnesota
Most snow on October 31
3.1 in (7.9 cm)
.5 in (1943)
Most snow on November 1
9.0 in (22.9 cm )
3 in (1920)
Sioux Falls, South Dakota
Earliest 6 in snowfall
11.2 in
m
Most snow in October
10.0 in
m
Twin Cities
Most snow on October 31
8.2 in (20.8 cm)
0.4 in (1 cm) (1954)
Most snow on November 1
18.5 in (47 cm)
3.6 in (9.1 cm) (1941)
24 hour snowfall in any season
21.0 in (53.3 cm)
18.5 in (47 cm) (January 23, 1982)
Most single storm snow total
28.4 in (72.9 cm)
20.0 in (50.8 cm) (Jan 22-23 1982)
Most snow in October
8.2 in (20.8 cm)
5.5 in (14 cm) (1905)
Earliest 8 inch snow
8.2 in (20.8 cm)
8.5 in (21.6 cm) (Nov 8, 1943)
Most snowfall in any month
46.9 in (119.1 cm) (Nov, 1991)
46.4 in (117.9 cm) (Jan, 1982)
Earliest autumn below zero low
-3 °F (-19 °C) (Nov 4)
-1 °F (-18 °C) (Nov 11, 1986)
Ice
Ice is water frozen into the solid state. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions...
accumulation that affected parts of the Upper Midwest
Upper Midwest
The Upper Midwest is a region in the northern portion of the U.S. Census Bureau's Midwestern United States. It is largely a sub-region of the midwest. Although there are no uniformly agreed-upon boundaries, the region is most commonly used to refer to the states of Minnesota, Wisconsin, and...
of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, from October 31 to November 3, 1991. Over the last week of October 1991 a large storm system over the Atlantic Ocean (1991 Perfect Storm) blocked most of the weather patterns over the eastern half of the United States, and in turn moisture from the Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
was funneled straight northward over the affected region. By the time the precipitation stopped falling many cities in the eastern half of Minnesota and northwestern Wisconsin had witnessed record early-season snowfall accumulations, while parts of southern Minnesota and northern Iowa were crippled by a large ice storm. Arctic
Arctic
The Arctic is a region located at the northern-most part of the Earth. The Arctic consists of the Arctic Ocean and parts of Canada, Russia, Greenland, the United States, Norway, Sweden, Finland, and Iceland. The Arctic region consists of a vast, ice-covered ocean, surrounded by treeless permafrost...
air that was pulled southward behind the storm had combined with the heavy snow pack to produce many record low temperatures. Between the blizzard and the ice storm 22 people were killed and over 100 were injured.
Meteorological synopsis
The Halloween Blizzard was made possible by a strong arctic cold frontArctic front
The Arctic front is a term used to describe the semipermanent, semi-continuous weather front between the cold arctic air mass and the warmer air of the polar cell. It can also be defined as the southern boundary of the Arctic air mass....
that pushed south and east through the central United States several days prior. On October 28 temperatures to the east of the cold front were above normal. High temperatures reached into the 70s from the middle Mississippi River Valley south into northern Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
, and into the 80s across much of central and southern Texas. Meanwhile, high temperatures did not reach 20 degrees across most of 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,...
and Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
.
The contrast between the two air masses was stark, and by the morning of October 29 the cold front was about halfway through Texas. At 6 AM CST, the temperature in the western Texas city of Amarillo
Amarillo, Texas
Amarillo is the 14th-largest city, by population, in the state of Texas, the largest in the Texas Panhandle, and the seat of Potter County. A portion of the city extends into Randall County. The population was 190,695 at the 2010 census...
had dropped to 22 degrees with a strong northerly breeze. Farther east in Texas the temperature was 64 in Dallas – a 42-degree temperature difference over about 300 miles. In the northern United States, morning lows were much colder. Temperatures were in the single digits across Montana and Wyoming and in the teens North Dakota
North Dakota
North Dakota is a state located in the Midwestern region of the United States of America, along the Canadian border. The state is bordered by Canada to the north, Minnesota to the east, South Dakota to the south and Montana to the west. North Dakota is the 19th-largest state by area in the U.S....
and 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...
.
By October 30, the cold front had pushed east to the Texas shoreline with the Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
, and stalled in that location. As an upper-level shortwave trough
Shortwave (meteorology)
A shortwave or shortwave trough is an embedded kink in the trough / ridge pattern. This is the opposite of longwaves, which are responsible for synoptic scale systems, although shortwaves may be contained within or found ahead of longwaves and range from the mesocale to the synoptic scale...
approached the Southern Plains
South Central United States
The South Central United States or South Central states is a region of the United States located in the south central part of the country. It evolved out of the archaic southwest, which originally was literally the western U.S. South...
, it aided the development of an area of surface low pressure along the sharp temperature gradient near the Texas Gulf Coast. The development of low-pressure systems along coastal fronts in this fashion is relatively common in the cool season along the Texas Gulf Coast and along the Atlantic Seaboard near the Gulf Stream
Gulf Stream
The Gulf Stream, together with its northern extension towards Europe, the North Atlantic Drift, is a powerful, warm, and swift Atlantic ocean current that originates at the tip of Florida, and follows the eastern coastlines of the United States and Newfoundland before crossing the Atlantic Ocean...
current.
From October 30 - 31, this low pressure system slowly became better organized over Texas, before it ejected north over the Mississippi River Valley. This meridonal trajectory
Meridional flow
Meridional flow is a meteorological term meaning that the general flow pattern is north to south, or south to north, along the Earth's longitude lines . Extratropical cyclones in this environment tend to be stronger and move slower...
of a low pressure track (almost due north from the western Gulf) is climatologically favorable to produce very heavy snowfall in the winter months because it allows copious amounts of moisture to flow north where it can interact with colder air. Cooler readings lingered at the very end of October across the Upper Midwest
Upper Midwest
The Upper Midwest is a region in the northern portion of the U.S. Census Bureau's Midwestern United States. It is largely a sub-region of the midwest. Although there are no uniformly agreed-upon boundaries, the region is most commonly used to refer to the states of Minnesota, Wisconsin, and...
, and a re-enforcing pool of Arctic air was just beginning to push southeast through the western Canadian Provinces.
On November 1, the surface low pressure moved north from western Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
into the Upper Peninsula of Michigan
Upper Peninsula of Michigan
The Upper Peninsula of Michigan is the northern of the two major land masses that make up the U.S. state of Michigan. It is commonly referred to as the Upper Peninsula, the U.P., or Upper Michigan. It is also known as the land "above the Bridge" linking the two peninsulas. The peninsula is bounded...
and the minimum pressure fell about 24 millibars in 24 hours, indicative of rapid deepening and strengthening of the cyclone. The low pressure eventually became occluded
Occluded front
An occluded front is formed during the process of cyclogenesis when a cold front overtakes a warm front. When this occurs, the warm air is separated from the cyclone center at the Earth's surface...
, weakened, and then continued to dissipate as it pushed east across northern Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
in subsequent days.
Precipitation
The precipitation from this system began falling as snow in Iowa late on October 30, and by the morning of October 31 it had changed over to ice and spread northward across southeast MinnesotaSoutheast Minnesota
Southeast Minnesota is the corner of Minnesota south of the Twin Cities metropolitan area extending east, and part of the multi-state area known as the Driftless Area. Rochester is the largest city in the area; other major cities include Winona, Owatonna, Faribault, Northfield, Austin, and Red...
. During Halloween day the precipitation spread to the north where it fell mostly as rapidly accumulating snow. The snow continued to develop northward, eventually spreading into the Minnesota Arrowhead
Arrowhead Region
The Arrowhead Region is located in the northeastern part of the U.S. state of Minnesota, so called because of its pointed shape. The predominantly rural region encompasses of land area and comprises Carlton, Cook, Lake and St. Louis Counties. Its population at the 2000 census was 248,425 residents...
. Eventually all of the precipitation changed over to snow, and in some areas it would continue falling until November 3.
Snow
The heavy snow began falling across east central Minnesota and northwest Wisconsin during the late afternoon hours of October 31. By midnight, the Twin CitiesMinneapolis-Saint Paul International Airport
Minneapolis-Saint Paul International Airport is the largest and busiest airport in the five-state upper Midwest region of Minnesota, Iowa, South Dakota, North Dakota, and Wisconsin.-Overview:...
had already recorded 8.2 in (20.8 cm) of snow. This not only set a record for the largest amount of snow on that date, but also for the most snow ever recorded in the Twin Cities during the month of October. As the storm system pushed its way northward, more communities in eastern Minnesota and northwestern Wisconsin began to experience similar conditions.
Duluth, Minnesota
Duluth is a port city in the U.S. state of Minnesota and is the county seat of Saint Louis County. The fourth largest city in Minnesota, Duluth had a total population of 86,265 in the 2010 census. Duluth is also the second largest city that is located on Lake Superior after Thunder Bay, Ontario,...
, the largest single snow storm total in Minnesota
Minnesota
Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
history at that time. The Twin Cities received 28.4 in (72.1 cm), setting a single-storm record for the metropolitan area. In all, at least one foot (30 cm) of snow fell in a swath approximately 100 mi (160 km) wide from south central Minnesota, northeastward into northwestern Wisconsin and into the Minnesota Arrowhead
Arrowhead Region
The Arrowhead Region is located in the northeastern part of the U.S. state of Minnesota, so called because of its pointed shape. The predominantly rural region encompasses of land area and comprises Carlton, Cook, Lake and St. Louis Counties. Its population at the 2000 census was 248,425 residents...
. A more narrow band of 2+ ft (60+ cm) of snow fell from the Twin Cities to Duluth and northward.
Ice
Areas of southern Minnesota and Iowa along and south of the I-90Interstate 90
Interstate 90 is the longest Interstate Highway in the United States at . It is the northernmost coast-to-coast interstate, and parallels US 20 for the most part. Its western terminus is in Seattle, at Edgar Martinez Drive S. near Safeco Field and CenturyLink Field, and its eastern terminus is in...
corridor did not see as much snow, but instead saw a major ice storm
Freezing rain
Freezing rain is the name given to rain that falls when surface temperatures are below freezing. The raindrops become supercooled while passing through a sub-freezing layer of air, many hundred feet , just above the surface, and then freeze upon impact with any object they encounter. The resulting...
. Though the precipitation started out as snow in these areas, it changed over to ice during the day on October 31 continued falling over the next day. Ice accumulations as high as 2–3 in (6 cm–9 cm) were recorded in these areas before the precipitation changed to snow. Up to 10 in (25.4 cm) of snow proceeded to fall on top of ice accumulations from the previous day, making travel even more treacherous. Up to 1 inch of ice accumulation was reported as far south as Omaha, Nebraska
Omaha, Nebraska
Omaha is the largest city in the state of Nebraska, United States, and is the county seat of Douglas County. It is located in the Midwestern United States on the Missouri River, about 20 miles north of the mouth of the Platte River...
.
Impact
Most of Minnesota, western Wisconsin and northern Iowa were heavily impacted by the storm. $63+ million in damages was reported from fallen power lines, and $5 million in crop damages were reported in Iowa. Eleven counties in southern Minnesota were declared federal disaster areas, and 52 counties in Iowa were declared disaster areas. At least 100,000 people lost power because of the weight of the ice downing power lines, and in some cases it took up to a week for the power to be restored.Many roads were closed both from the snow and ice, including long stretches of I-90, I-35 and I-29 in Iowa, Minnesota and South Dakota. Highway snow removal was hindered by record cold temperatures that followed the storm and transportation was hampered for many days. Nine hundred schools and business were closed in Minnesota alone. Twenty two people died in this storm, twenty in Minnesota and two on the Mississippi River near La Crosse.
Records
In eastern Minnesota, the Halloween Blizzard shattered many of the previous October snowfall records. The 8.2 inches that fell in the Twin Cities on October 31 was more snow than had ever been recorded in any October in its recorded history. November 1 saw similar daily records fall, but with a more wide reaching area from most of central Minnesota eastward to La CrosseLa Crosse, Wisconsin
La Crosse is a city in and the county seat of La Crosse County, Wisconsin, United States. The city lies alongside the Mississippi River.The 2011 Census Bureau estimates the city had a population of 52,485...
and Eau Claire, Wisconsin
Eau Claire, Wisconsin
Eau Claire is a city located in the west-central part of the U.S. state of Wisconsin. The population was 65,883 as of the 2010 census, making it the largest municipality in the northwestern portion of the state, and the 9th largest in the state overall. It is the county seat of Eau Claire County,...
. Following the storm Arctic air poured southward from Canada to produce many record low temperatures in these same areas. Bismarck, North Dakota
Bismarck, North Dakota
Bismarck is the capital of the U.S. state of North Dakota and the county seat of Burleigh County. It is the second most populous city in North Dakota after Fargo. The city's population was 61,272 at the 2010 census, while its metropolitan population was 108,779...
, sank to −10 °F on October 31, breaking their previous record low of 6 °F by 16 degrees. Record snow and cold was recorded as far south as Nebraska and Colorado. The Arctic air also spread over Chicago, recording a low of 11 on November 4.
Four weeks later on November 29–30, another large storm system dropped as much as 18 inches of snow over these same areas. These two storms combined to set a single-month record for most snowfall in the Twin Cities and Duluth.