Snow removal
Encyclopedia
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...
after a snowfall to make travel easier and safer. This is done by both individual households and by governments and institutions.
De-icing and anti-icing
De-icing is defined as removal of existing, snow ice, frost, etc., from a surface. It includes both mechanical (plowing or scraping) or chemical (application of salt or other ice melting chemicals) methods.Anti-icing is defined as the pretreatment of a roadway, sidewalk or parking lot with ice melting chemicals before a storm, to prevent or delay the formation of ice, or the adhesion of ice and snow. Brine or wetted salt is usually applied shortly before a snowstorm arrives. Properly performed, anti-icing can significantly reduce the amount of salt required, and allows easier removal by mechanical methods (snowplows).
De-icing of road
Road
A road is a thoroughfare, route, or way on land between two places, which typically has been paved or otherwise improved to allow travel by some conveyance, including a horse, cart, or motor vehicle. Roads consist of one, or sometimes two, roadways each with one or more lanes and also any...
s has traditionally been done with salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
, spread by snowplow
Snowplow
A snowplow is a device intended for mounting on a vehicle, used for removing snow and ice from outdoor surfaces, typically those serving transportation purposes...
s or dump truck
Dump truck
A dump truck is a truck used for transporting loose material for construction. A typical dump truck is equipped with a hydraulically operated open-box bed hinged at the rear, the front of which can be lifted up to allow the contents to be deposited on the ground behind the truck at the site of...
s designed to spread it, often mixed with sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
and gravel
Gravel
Gravel is composed of unconsolidated rock fragments that have a general particle size range and include size classes from granule- to boulder-sized fragments. Gravel can be sub-categorized into granule and cobble...
, on slick roads. Sodium chloride
Sodium chloride
Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...
(rock salt) is normally used, as it is inexpensive
Cost
In production, research, retail, and accounting, a cost is the value of money that has been used up to produce something, and hence is not available for use anymore. In business, the cost may be one of acquisition, in which case the amount of money expended to acquire it is counted as cost. In this...
and readily available in large quantities. However, since salt water
Brine
Brine is water, saturated or nearly saturated with salt .Brine is used to preserve vegetables, fruit, fish, and meat, in a process known as brining . Brine is also commonly used to age Halloumi and Feta cheeses, or for pickling foodstuffs, as a means of preserving them...
still freezes at -18°C or 0°F, it is of no help when the temperature falls below this point. It also has a strong tendency to cause corrosion
Corrosion
Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...
, rust
Rust
Rust is a general term for a series of iron oxides. In colloquial usage, the term is applied to red oxides, formed by the reaction of iron and oxygen in the presence of water or air moisture...
ing the steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
used in most vehicles and the rebar
Rebar
A rebar , also known as reinforcing steel, reinforcement steel, rerod, or a deformed bar, is a common steel bar, and is commonly used as a tensioning device in reinforced concrete and reinforced masonry structures holding the concrete in compression...
in concrete bridges. More recent snowmelters use other salts, such as calcium chloride
Calcium chloride
Calcium chloride, CaCl2, is a salt of calcium and chlorine. It behaves as a typical ionic halide, and is solid at room temperature. Common applications include brine for refrigeration plants, ice and dust control on roads, and desiccation...
and magnesium chloride
Magnesium chloride
Magnesium chloride is the name for the chemical compounds with the formulas MgCl2 and its various hydrates MgCl2x. These salts are typical ionic halides, being highly soluble in water. The hydrated magnesium chloride can be extracted from brine or sea water...
, which not only depress the freezing point of water to a much lower temperature, but also produce an exothermic reaction
Exothermic reaction
An exothermic reaction is a chemical reaction that releases energy in the form of light or heat. It is the opposite of an endothermic reaction. Expressed in a chemical equation:-Overview:...
. They are somewhat safer for concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
sidewalk
Sidewalk
A sidewalk, or pavement, footpath, footway, and sometimes platform, is a path along the side of a road. A sidewalk may accommodate moderate changes in grade and is normally separated from the vehicular section by a curb...
s, but excess should still be removed.
More recently, organic compounds have been developed that reduce the environmental issues connected with salts and have longer residual effects when spread on roadways, usually in conjunction with salt brines or solids. These compounds are generated as byproducts of agricultural operations such as sugar beet
Sugar beet
Sugar beet, a cultivated plant of Beta vulgaris, is a plant whose tuber contains a high concentration of sucrose. It is grown commercially for sugar production. Sugar beets and other B...
refining or the distillation
Distillation
Distillation is a method of separating mixtures based on differences in volatilities of components in a boiling liquid mixture. Distillation is a unit operation, or a physical separation process, and not a chemical reaction....
process that produces ethanol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
. Additionally, mixing common rock salt with some of the organic compounds and magnesium chloride results in spreadable materials that are both effective to much colder temperatures (-30°F/-34°C) as well as at lower overall rates of spreading per unit area.
Since the 1990s, use of liquid chemical melters has been increasing, sprayed
Sprayer
A sprayer is a device used to spray a liquid.In agriculture, a sprayer is a piece of equipment that spray nozzles to apply herbicides, pesticides, and fertilizers to agricultural crops...
on roads by nozzles instead of a spinning spreader. Liquid melters are more effective at preventing the ice from bonding to the surface than melting through existing ice.
Several proprietary products incorporate anti-icing chemicals into the pavement. Verglimit incorporates calcium chloride granuals into asphalt pavement. The granuals are continually exposed by traffic wear, and release calcium chloride onto the surface. This prevents snow and ice from sticking to the pavement
Cargill SafeLane is a proprietary pavement surface treatment that absorbs anti-icing brines, to be released during a storm or other icing event. It also provides a high-friction surface, increasing traction.
In Nagano
Nagano, Nagano
, the capital city of Nagano Prefecture, is located in the northern part of the prefecture near the confluence of the Chikuma and the Sai rivers, on the main Japanese island of Honshū.As of April 1, 2011 the city has a population of 387,146...
, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, relatively inexpensive hot water bubbles up through holes in the pavement to melt snow, though this solution is only practical within a city
City
A city is a relatively large and permanent settlement. Although there is no agreement on how a city is distinguished from a town within general English language meanings, many cities have a particular administrative, legal, or historical status based on local law.For example, in the U.S...
or town
Town
A town is a human settlement larger than a village but smaller than a city. The size a settlement must be in order to be called a "town" varies considerably in different parts of the world, so that, for example, many American "small towns" seem to British people to be no more than villages, while...
. Some individual buildings may melt snow and ice with electric
Electric power
Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt.-Circuits:Electric power, like mechanical power, is represented by the letter P in electrical equations...
heating element
Heating element
A heating element converts electricity into heat through the process of Joule heating. Electric current through the element encounters resistance, resulting in heating of the element....
s buried in the pavement, or even on a roof
Roof
A roof is the covering on the uppermost part of a building. A roof protects the building and its contents from the effects of weather. Structures that require roofs range from a letter box to a cathedral or stadium, dwellings being the most numerous....
to prevent ice dams under the shingles
Roof shingle
Roof shingles are a roof covering consisting of individual overlapping elements. These elements are typically flat rectangular shapes laid in rows from the bottom edge of the roof up, with each successive higher row overlapping the joints in the row below...
, or to keep massive chunks of snow and dangerous icicle
Icicle
An icicle is a spike of ice formed when water dripping or falling from an object freezes. Typically, icicles will form when ice or snow is melted by either sunlight or some other heat source , and the resulting melted water runs off into an area where the ambient temperature is below the freezing...
s from collapsing on anyone below. Small areas of pavement can be kept ice-free by circulating heated liquids in embedded piping systems.
Clearing by individuals
In places with light snow, brooms or other light instruments can be used to brush off snow from walks and other surfaces. In regions with more precipitation, snow is commonly removed with snow shovels, a large lightweight shovel used to push snow and lift it, and snow scoops or sleigh shovels, a large and deep hopper-like implement fitted with a wide handle and designed to scoop up a load of snow and slide it on any slippery surface to another location without lifting. Other tools include snow pusher
Snow pusher
Snow pushers are designed to move snow by pushing it straight ahead. They do this by being constructed with a curved moldboard that lies perpendicular to the direction of travel and a sidewall at either end that keeps the snow contained. For parking lots, runways, etc...
s and shovels with one or more wheels.
Shovelling entails a considerable amount of physical effort and can strain the back
Back
- People :* Adam Back, British cryptographer* Charles Back, South African winemaker* Chris Back , Australian politician* Ernst Emil Alexander Back , German physicist* Frédéric Back , Canadian animator...
and the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
. Each year many senior citizens and middle aged persons die from heart attacks while shovelling snow.
Snow blower
Snow blower
A snow blower or snow thrower is a machine for removing snow from an area where it is not wanted, such as a driveway, sidewalk, roadway, railroad track, rink, runway, or houses...
s are often used by people unwilling or unable to perform this labour, people with large driveway
Driveway
A driveway is a type of private road for local access to one or a small group of structures, and is owned and maintained by an individual or group....
s or other substantial surfaces and people that live in areas with long lasting winters with large amounts of snowfall. Others may hire a contractor with a plow bearing truck or a shovel. After a large snowfall, businessmen with plow trucks often drive through cities offering to plow for money.
Removing ice is more difficult. Snow blowers are usually ineffective for clearing ice. Picks are sometimes used, but a solid spade
Spade
A spade is a tool designed primarily for the purpose of digging or removing earth. Early spades were made of riven wood. After the art of metalworking was discovered, spades were made with sharper tips of metal. Before the advent of metal spades manual labor was less efficient at moving earth,...
can break through most ice. There is always the risk of damaging the pavement with these instruments. Icy areas can be covered with salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
or some other substance, bags of which are widely available.
A recent technological advance is the snowmelt system
Snowmelt system
A snowmelt system is used to remove snow and ice via embedded electric cables or hydronic tubing. Common areas for snowmelt systems are: driveways, walkways, parking areas, stairways, loading docks, and around car washes. A snowmelt system is usually installed during the original construction in...
that heats the pavement from below and melts snow and ice after a period of time. Such systems are expensive to install and operate and they are not cost effective in areas with very low winter temperatures and large snowfalls.
Some governments offer free snow clearing for the elderly and others in need. In some cities, snow clearing for elder and handicapped residents counts towards community service hours assigned as a punishment for minor offences.
In many places, laws require homeowners to clear snow from the public sidewalk
Sidewalk
A sidewalk, or pavement, footpath, footway, and sometimes platform, is a path along the side of a road. A sidewalk may accommodate moderate changes in grade and is normally separated from the vehicular section by a curb...
in front of their house, as well as a pathway on their own property to their mailbox
Mailbox
Mailbox may refer to:* Letter box, copper box, or other sturdy material compartment, or slot for incoming postal deliveries.* Post box, a physical box for outgoing postal deliveries....
. Those who fail to do so, depending on the jurisdiction's laws, may face fines and may be civilly liable for injuries suffered by another on a surface that they were required to clear. In some jurisdictions, such as New York, private home owners who shovel are held civilly liable for others' injuries incurred by falling in areas that have been shovelled.
Cleaning off and freeing one's vehicle is another matter. Many people who need their vehicles will do just barely what is necessary in order to drive the vehicle and remove it from its space. Failure to clear all the snow and ice off a vehicle causes hazards by restricting the driver's visbility, and ice from the roofs of driven vehicles can cause crashes. In some jurisdictions, motorists who fail to completely clean snow off their vehicle can be fined. Others may be more thorough in this process.
In many urban residential areas with curbside parking, residents use objects to mark the spaces they dug out so they can reclaim their space upon their return.
Cleaning by the owners of the contiguous lands or buildings
In some countries, to ensure the winter trafficability of sidewalks belongs to duties of the owner of the contiguous land or building. Such owner can be an individual inhabitant, in case of a family house, but also the municipality, municipal district or their specific organization or a housing co-operative or some other company (especially if some office or industrial object is concerned). Owners of large buildings or building complexes generally have mechanized snow-removal equipment, but individual house owners mostly clean the sidewalk with hand tools.For example, in Prague
Prague
Prague is the capital and largest city of the Czech Republic. Situated in the north-west of the country on the Vltava river, the city is home to about 1.3 million people, while its metropolitan area is estimated to have a population of over 2.3 million...
, a persistency of such duty is documented since 1838. The decree of the government of Protectorate of Bohemia and Moravia
Protectorate of Bohemia and Moravia
The Protectorate of Bohemia and Moravia was the majority ethnic-Czech protectorate which Nazi Germany established in the central parts of Bohemia, Moravia and Czech Silesia in what is today the Czech Republic...
No 1/1943 Sb. said that sidewalk cleaning in residential area in municipalities with more than 5000 inhabitants, district cities and other specified municipalities is a duty of the owner or user of the contiguous land. The municipality was empowered to undertake this duty at the expense of the contiguous land owner. The Czechoslovak Road Act No 135/1961 Sb. (§ 23) adopted such legal regulations for all municipalites, but municipality offices might modify them. The new Road Act of the Czech Republic, No 13/1997 Sb. (§ 9 art. 4) left this enactment and stated that way maintenance is an obligation of the way owner, without any exception. Despite of it, § 27 art. 4 attached to the contiguous land owner the liability for harm caused by defects of cleaning. The Czech Public Defender of Rights claimed in 2002 and 2003 annual reports the discrepancy between theoretical and practical interpretations of the act and recommended to enact an unequivocal formulation. This discrepance was repeatedly handled by courts and the Supreme Administrative Court on 2005 June 27 and the Constitutional Court on 2007 January 3-rd stated that the cleaning duty results indirectly from the stated liability for harm. Impugners of the duty argued that this duty is a residue of feudal corvée or of totalitarian nazism and communistic regimes and that nowadays, compulsory labour at extrinsic way is in conflict with Charter of Fundamental Rights and Basic Freedoms
Charter of Fundamental Rights and Basic Freedoms
The Charter of Fundamental Rights and Basic Freedoms is a document enacted in 1991 by the Czechoslovak Federal Republic, and continued as part of the great constitutional systems of both the Czech Republic and Slovak Republic...
, and that systematic municipal cleaning is more effective than a cleaning by individuals. On December 6, 2007, the Senate of the Czech Republic
Senate of the Czech Republic
The Senate of the Parliament of the Czech Republic , usually referred to as Senát, is the upper chamber of the Parliament of the Czech Republic...
proposed at the instance of its Constitutional Committee to let out the controversial article. The Czech Government give support to it by their narrow majority. Past heated debate, the Chamber of Deputies of the Czech Republic
Chamber of Deputies of the Czech Republic
The Chamber of Deputies of the Parliament of the Czech Republic is the lower house of the bicameral Parliament of the Czech Republic. The seat of the Chamber of Deputies is situated in palaces in Malá Strana, Prague....
sanctioned this change by 116:31 ratio from 190 presenting members. Since 2009 April 16-th, the change made by the act No 97/2009 Sb. is forcing and sidewalk cleaning is an obligation of the sidewalk owner only, i. e. generally the municipality. In despite of duty abolition, many people including oppugnants of the duty declared that they will to continue the winter cleaning of municipal sidewalks, but voluntarily and on their own behalf.
As was mentioned during the discussion at the Czech Parliament
Parliament of the Czech Republic
The Parliament of the Czech Republic is the legislative body of the Czech Republic, based in Prague. It consists of two chambers, both elected in direct elections:* the Lower House: Chamber of Deputies of the Parliament of the Czech Republic...
by the statement of the Czech Association of Cities and Municipalities, similar duty remains in many other modern countries, e. g. Austria
Austria
Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...
, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
and some cities of Bavaria
Bavaria
Bavaria, formally the Free State of Bavaria is a state of Germany, located in the southeast of Germany. With an area of , it is the largest state by area, forming almost 20% of the total land area of Germany...
and USA.
Clearing by contractors
In many high elevation or heavy snow accumulating areas, companies with snow removal equipment offer to provide services to remove the snow. Contractors may work on a per-time basis, full season contract, or will-call status. Per-time service (or per-push) is usually invoiced monthly and customers will be charged for each time services are provided. Some companies will charge per-time and per-inch where the depth of the snow is even taken into account. A full season contract is quoted and paid upfront at the start of the season and services will be provided automatically according to the contracted terms. All companies have different terms so make sure to understand the agreement. For example, some full season contracts will expire after X amount of trips where others are unlimited. And finally, will-call service is where the client makes contact with the snow removal company to initiate a single clearing. This is not an automatic service and charges are usually higher for will-call jobs.
Snow removal services may include driveway and parking area snow removal, walkway and deck handwork, and occasionally roof clearing. Contractors use hand shovels, walk behind snowblowers (or snow throwers), truck plows, skid-steers, light-weight tractors, and heavy front-end loaders. Many times, these machines will require use of tire chains to perform their tasks. Snow may be pushed by plowing methods or blown to an area of the property by snowblowers. Contracts may apply sand or salt in some locations to help melt ice accumulations.
Many snow removal contractors will require installation of snow poles or snow staking along the driveway. This is to keep equipment out of the landscaping and to help identify the perimeter of an area.
Contractors should be licensed and insured.
Clearing by cities
Cities clear snow on a much larger scale than individuals. Most cities in areas that get regular snow maintain a fleet of snow clearing vehicles. The first to be dispatched are gritters who do some plowing but also salt the road. The salt, via freezing point depression, helps melt the snow and ice and also gives vehicles more traction. Later, generally once the snow has ceased falling, snow plows, front end loaderFront End Loader
Front End Loader is an Australian rock band consisting of Davis Claymore , Bowden Campbell , Richard Corey , and Peter Kostic . Peter also drums for Regurgitator and The Hard-Ons.-History:...
s with snowplow attachments and grader
Grader
A grader, also commonly referred to as a road grader, a blade, a maintainer, or a motor grader, is a construction machine with a long blade used to create a flat surface. Typical models have three axles, with the engine and cab situated above the rear axles at one end of the vehicle and a third...
s cover every street pushing snow to the side of the road. Salt trucks often then return to deal with any remaining ice and snow. The trucks generally travel much faster than the plows, averaging between 30 and 40 kilometers per hour. Most cities thus have at least twice as many plows as trucks. Smaller narrow body plows, with Caterpillar tracks or huge snow tires salt and clear sidewalk
Sidewalk
A sidewalk, or pavement, footpath, footway, and sometimes platform, is a path along the side of a road. A sidewalk may accommodate moderate changes in grade and is normally separated from the vehicular section by a curb...
s in some cities, but in many others with less snow fall and/or less pedestrian traffic individuals are tasked with clearing the sidewalk in front of their homes. Ecological movements often oppose this use of salt because of the damage it does when it eventually washes off the roads and spreads to the environment in general.
In cities where snow steadily accumulates over the winter it is also necessary to remove the piles of snow that build up on the side of the roads known as windrow
Windrow
A windrow is a row of cut hay or small grain crop. It is allowed to dry before being baled, combined, or rolled. For hay, the windrow is often formed by a hay rake, which rakes hay that has been cut by a mower machine or by scythe into a row, or it may naturally form as the hay is mowed...
s or snowbanks. There are a number of methods of doing this. Pulling snow is done when temperatures rise high enough for traffic to melt snow. The windrows are then broken up and spread over the road. Casting is the moving of snow by means of a shovel or plow to nearby public lands. On boulevards or highways winging back is done, which consists of pushing the snow banks further from the road. The most expensive option, but necessary when there are no nearby places to dump the snow, is to haul it away. This is most often done by large self propelled snowblowers that gather the piles of snow at the side of the road and load it into dump truck
Dump truck
A dump truck is a truck used for transporting loose material for construction. A typical dump truck is equipped with a hydraulically operated open-box bed hinged at the rear, the front of which can be lifted up to allow the contents to be deposited on the ground behind the truck at the site of...
s. The snow is then dumped on the outskirts of town, or in a nearby lake, river or harbor. (Some jurisdictions have banned dumping snow into local bodies of water for environmental reasons - modern roads can be contaminated with melting salt, motor oil, and other substances.) Snow melting machines may be cheaper than moving snow, depending on the cost of fuel and the ambient temperature.
The windrows created by the plows in residential areas often block driveways and imprison parked cars. The snow pushed there by any plow is a dense, packed version of "normal" fallen snow. When the temperatures are significantly below freezing this packed snow takes some of the characteristics of solid ice. Its removal is nearly impossible without mechanical means.
Bus
A bus is a road vehicle designed to carry passengers. Buses can have a capacity as high as 300 passengers. The most common type of bus is the single-decker bus, with larger loads carried by double-decker buses and articulated buses, and smaller loads carried by midibuses and minibuses; coaches are...
es and other mass transit are also often given higher priorities. It often takes many hours, or even days, to cover every street in a city. In some places, a snow emergency
Snow emergency
A Snow Emergency is the term used to indicate the active response plan when a snow storm severely impacts a city, county or town in the United States or Canada. Schools, universities, government offices, airports and public buildings may close during a Snow Emergency. The precise meaning of "snow...
will be declared, where automobile owners are instructed to remove their vehicles from the street (or one side of a street). If cars are in the way when the plows come around, they may be hauled away by tow truck
Tow truck
A tow truck is a vehicle used to transport motor vehicles to another location , or to recover vehicles which are no longer on a drivable surface.Towing services are generally provided by an emergency road service operator...
s. Some communities have standing snow emergency rules in winter, where vehicles are not allowed to be parked on streets overnight, no matter if it snows or not. After smaller snow storms only main roads are cleared while residential ones are left to be melted by the passing traffic. Decisions on immediate removal versus "natural melting" can be hard to make because the inconvenience to citizens and the economy in general must be weighed against the immediate effect on the snow removal budget at that particular moment in the season.
In large cities with heavy snowfalls like Montreal
Montreal
Montreal is a city in Canada. It is the largest city in the province of Quebec, the second-largest city in Canada and the seventh largest in North America...
and Ottawa
Ottawa
Ottawa is the capital of Canada, the second largest city in the Province of Ontario, and the fourth largest city in the country. The city is located on the south bank of the Ottawa River in the eastern portion of Southern Ontario...
, the snow clearing expense for each season is an important part of the seasonal public works budget and each snow storm provokes a major logistical operation involving thousands of employees working in shifts 24 hours a day. The effort can vary greatly depending on the amount of snow. Montreal gets about 225 cm of snow each winter and spends more than $128 million Canadian each year to remove it. Toronto
Toronto
Toronto is the provincial capital of Ontario and the largest city in Canada. It is located in Southern Ontario on the northwestern shore of Lake Ontario. A relatively modern city, Toronto's history dates back to the late-18th century, when its land was first purchased by the British monarchy from...
, with about 50 per cent more population and 28 per cent more road surface, gets only 125 cm of snow a year and spends about half that. The higher cost in Montreal is due to the need to perform "snow removal" as opposed to simple "snow clearing" necessitated by both the high snowfall amounts and fewer melting days.
In Helsinki
Helsinki
Helsinki is the capital and largest city in Finland. It is in the region of Uusimaa, located in southern Finland, on the shore of the Gulf of Finland, an arm of the Baltic Sea. The population of the city of Helsinki is , making it by far the most populous municipality in Finland. Helsinki is...
, Finland amount of snow transported from streets and properties to snow dump sites during the winter of 2009–2010
Winter of 2009–2010 in Europe
The winter of 2009–2010 in Europe was unusually cold. Globally, atypical weather patterns brought cold, moist air from the north. Weather systems were undergoing cyclogenesis from North American storms moving across the Atlantic Ocean to the west, and saw many parts of Europe experiencing heavy...
was 210,000 truckloads, equaling over 3 million cubic meters.
Snow removal impacts the design of city infrastructure. Where possible, street boulevards are wider to accommodate the windrows and sidewalks are not right next to the street. Fire hydrant
Fire hydrant
A fire hydrant , is an active fire protection measure, and a source of water provided in most urban, suburban and rural areas with municipal water service to enable firefighters to tap into the municipal water...
s will have tall flags to locate them under the windrows. Reflective traffic lane markers embedded in the roadbed is not possible (or much harder) due to risk of damage by plows. Access to snow dumping locations (e.g. ravines) by heavy equipment is also planned.
It is estimated that Canada spends $1 billion on snow removal. The employees who do this work are generally the same workers who do road maintenance work during the summer months, but in some US cities garbage trucks are also equipped with plows and used for snow removal. Many smaller US communities sign contracts with insurance companies, under which the insurance company assumes the risk of a heavy winter. The insurance company of course sets the rates such that averaged over time they will make a profit; the town is willing to overpay for snow removal in mild winters so as to avoid the risk of running dramatically over budget in the occasional severe winter.
Large organizations such as universities
University
A university is an institution of higher education and research, which grants academic degrees in a variety of subjects. A university is an organisation that provides both undergraduate education and postgraduate education...
and airport
Airport
An airport is a location where aircraft such as fixed-wing aircraft, helicopters, and blimps take off and land. Aircraft may be stored or maintained at an airport...
s also often have their own mechanized snow clearing force. Public transit systems generally clear bus stops while post office
Post office
A post office is a facility forming part of a postal system for the posting, receipt, sorting, handling, transmission or delivery of mail.Post offices offer mail-related services such as post office boxes, postage and packaging supplies...
s clear around mail box
Post box
A post box is a physical box into which members of the public can deposit outgoing mail intended for collection by the agents of a country's postal service...
es. Railroads have their own snow clearing devices such as rotary snowplow
Rotary snowplow
A rotary snowplow is a piece of railroad snowfighting equipment. It is characterized by the large circular set of blades on its front end that rotate as a unit to cut through the snow on the track ahead of it.-History:...
s.
Surface treatments
The surface is treated primarily by snow removal. Roads are also treated by spreading various materials on the surface. These materials generally fall into two categories: chemical and inert. Chemical (including salt) distribution induces freezing-point depressionFreezing-point depression
Freezing-point depression describes the phenomenon in which the freezing point of a liquid is depressed when another compound is added, meaning that a solution has a lower freezing point than a pure solvent. This happens whenever a non-volatile solute is added to a pure solvent, such as water...
, causing ice and snow to melt at a lower temperature. Chemical treatment can be applied as a preventive measure and/or after snowfall. Inert materials (i.e. sand, brash, slag) make the surface irregular to improve traction. Both types can be applied together, but the inert materials tend to lower traction once the snow and ice has melt.
Chemical treatment materials include:
- Sodium chlorideSodium chlorideSodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...
(common table salt, NaCl) - Calcium chlorideCalcium chlorideCalcium chloride, CaCl2, is a salt of calcium and chlorine. It behaves as a typical ionic halide, and is solid at room temperature. Common applications include brine for refrigeration plants, ice and dust control on roads, and desiccation...
(CaCl2) - Potassium chloridePotassium chlorideThe chemical compound potassium chloride is a metal halide salt composed of potassium and chlorine. In its pure state, it is odorless and has a white or colorless vitreous crystal appearance, with a crystal structure that cleaves easily in three directions. Potassium chloride crystals are...
(KCl) - Magnesium chlorideMagnesium chlorideMagnesium chloride is the name for the chemical compounds with the formulas MgCl2 and its various hydrates MgCl2x. These salts are typical ionic halides, being highly soluble in water. The hydrated magnesium chloride can be extracted from brine or sea water...
(MgCl2) - Ammonium nitrate (NH4NO3)
- Ammonium sulfateAmmonium sulfateAmmonium sulfate , 2SO4, is an inorganic salt with a number of commercial uses. The most common use is as a soil fertilizer. It contains 21% nitrogen as ammonium cations, and 24% sulfur as sulfate anions...
[(NH4)2SO4] - Potassium acetatePotassium acetatePotassium acetate is the potassium salt of acetic acid.-Preparation:It can be prepared by reacting a potassium-containing base such as potassium hydroxide or potassium carbonate with acetic acid:...
(CH3COOK) - UreaUreaUrea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....
[(NH2)2CO] - Propylene glycolPropylene glycolPropylene glycol, also called 1,2-propanediol or propane-1,2-diol, is an organic compound with formula C3H8O2 or HO-CH2-CHOH-CH3...
(C3H8O2) - Calcium magnesium acetateCalcium Magnesium AcetateCalcium magnesium acetate is a deicer and can be used as an alternative to road salt. It is approximately as corrosive as normal tap water, and in varying concentrations can be effective in stopping road ice from forming down to around...
(C4H6O2Ca and C4H6O2Mg) - Sodium ferrocyanideSodium ferrocyanideSodium ferrocyanide is the sodium salt of the coordination compound of formula [Fe6]4-. It is a yellow crystalline solid that is soluble in water and insoluble in alcohol. Despite the presence of the cyanide ligands, sodium ferrocyanide is not especially toxic because the cyanides are tightly...
(hydrous, Na4Fe(CN)6•10H2O) - Methyl alpha-D-glucopyranoside (C7H14O6)
In the European Union, ca 98% of chemical treatment materials used in 2000 were sodium chloride
Sodium chloride
Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...
in various forms. It is effective down to −5 °C, at the most −7 °C. For colder temperatures, calcium chloride
Calcium chloride
Calcium chloride, CaCl2, is a salt of calcium and chlorine. It behaves as a typical ionic halide, and is solid at room temperature. Common applications include brine for refrigeration plants, ice and dust control on roads, and desiccation...
(CaCl2) is added to NaCl in some countries, but deployment is limited as it costs about 6 times as much as sodium chloride. Other substances were used rarely and experimentally. Alternative substances (urea, alcohols, glycols) are often used at airports. In recent years, Geomelt, a combination of salt brine and beet juice that is otherwise considered a waste product has been used for pretreatment.
Inert spreadings can be:
- sandSandSand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
- brashBrashBrash may refer to:* Thomas Brash Morison , Scottish politician and judge* Brash Brands* Brash, a hip hop artist from CT, and founder of Aeon Audio* Brash Entertainment, a video game company* Olof the Brash...
, rubbleRubbleRubble is broken stone, of irregular size, shape and texture. This word is closely connected in derivation with "rubbish", which was formerly also applied to what we now call "rubble". Rubble naturally found in the soil is known also as brash...
etc. - slagSlagSlag is a partially vitreous by-product of smelting ore to separate the metal fraction from the unwanted fraction. It can usually be considered to be a mixture of metal oxides and silicon dioxide. However, slags can contain metal sulfides and metal atoms in the elemental form...
- wood ashWood ashWood ash is the residue powder left after the combustion of wood. Main producers of wood ash are wood industries and power plants.-Composition:...
(for household use only) - sawdustSawdustSawdust is a by-product of cutting lumber with a saw, composed of fine particles of wood. It can present a hazard in manufacturing industries, especially in terms of its flammability....
The choice of treatment may include consideration of the effect on vegetation, pets and other animals, the local watershed
Drainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...
, and effectiveness with regard to speed and temperature. Some chemicals can degrade concrete
Concrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
, metals, and other materials. The resulting meltwater
Meltwater
Meltwater is the water released by the melting of snow or ice, including glacial ice and ice shelfs over oceans. Meltwater is often found in the ablation zone of glaciers, where the rate of snow cover is reducing...
and slush
Slush
Slush can mean any of the following:* Slush — a slurry mixture of liquid and solid forms of water.* Slush — a pejorative and slang combination of the likewise derogatory terms slut and lush...
can cause frost heaving
Frost heaving
Frost heaving results from ice forming beneath the surface of soil during freezing conditions in the atmosphere. The ice grows in the direction of heat loss , starting at the freezing front or boundary in the soil...
if it re-freezes, which can also damage pavement. Inert materials can damage vehicles and create dust.
As an example, in the Czech Republic
Czech Republic
The Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest....
during the winter season of 2000/2001, net material expenditure for road treatment was: 168 000 tonnes of salt (mostly NaCl), 348 000 tonnes of sand and crushed stone and 91 000 tonnes of other materials like slag. In Ireland
Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...
, the annual expenditure of salt was 30 000 tonnes. Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
reports their annual expenditure as 600 grammes of salt to every square metre of roads on average.
Snow removal tools
- Snow shovel
- Snow blowerSnow blowerA snow blower or snow thrower is a machine for removing snow from an area where it is not wanted, such as a driveway, sidewalk, roadway, railroad track, rink, runway, or houses...
- SnowplowSnowplowA snowplow is a device intended for mounting on a vehicle, used for removing snow and ice from outdoor surfaces, typically those serving transportation purposes...
- Ice pick
- SpadeSpadeA spade is a tool designed primarily for the purpose of digging or removing earth. Early spades were made of riven wood. After the art of metalworking was discovered, spades were made with sharper tips of metal. Before the advent of metal spades manual labor was less efficient at moving earth,...
- Snow melter