Living with Snow
Snow affects people everywhere through its indirect effects on climate, water supply, and ecosystems. For people who live in snowy climates, however, snow has direct and tangible impacts on daily life.
For most of human history, people adapted to living with snow through invention and use of specialized snow tools and technologies, including the development and use of over-snow modes of transportation, and adjustment of life activities according to the obstacles and opportunities provided by different seasons. During the past two centuries, people’s relationship with their environment has shifted from one in which people modify their lives to accommodate natural conditions to one in which we actively modify the environment to accommodate our lifestyles. This is especially true when it comes to transportation in snowy places.
Transportation and Snow Removal
Humans inhabiting snowy areas of the Northern Hemisphere have traveled in and over snow by snowshoe, ski, and animal-drawn sleds or sleighs for thousands of years. With the transition from dispersed rural settlements to more densely populated urban areas in North America in the 1800s and 1900s and the change from a subsistence-based to a cash economy that required travel for purchasing and delivering supplies and between home and work locations, it became more practical to move by horse-drawn sleighs that could carry larger, heavier loads and travel farther and faster than a person on foot, snowshoe, or dog sled. To facilitate travel by sleigh, it became common practice to pack down snow on main roads in cities (Soniak, 2015), which started a trend toward altering rather than adjusting to the snow environment.
With the advent of motorized transportation, removing snow from the roadways became the goal. The first snow plows appeared in the 1840s but were not widely used until 1862, when Minneapolis became the first city in the U.S. to use a snow plow to clear city streets (“Winter service vehicle,” 2020). Early snow removal equipment did not much resemble the vehicle-mounted wedge plow that we are familiar with today, however. One 1920s invention, called a snow loader, used a large scoop to move snow onto a conveyor belt that eventually deposited the snow in a dumptruck, which in turn transported snow to be unloaded in another location (Cheshire, 1997).
By the 1800s, trains were becoming essential for moving people and goods year round. In order to remove snow from tracks, trains used wooden wedge plows attachments to push snow out of the way as they moved forward. In areas that received large amounts of snow, however, this method resulted in a narrow pathway along the tracks with steep walls of snow along the sides, presenting a situation in which there was no more room to move the snow out of the way. The use of mechanized, rotor-style plows solved this problem. Using the same technology used in today’s hand-held snow blowers, these train-mounted devices drew snow into a rotor that projected the snow into the air to be deposited farther afield (“Rotary Snowplow,” 2020).
When big snow storms shut down cities for days at a time, as in the 1888 storm that deposited more than four feet of snow in some areas of the Northeast and brought cities to a grinding halt, local governments began getting serious about municipal snow removal. Snow removal began to be seen as the responsibility of the government, and plowing became a season-long maintenance activity rather than an emergency measure to be taken only after storms.
Today, the U.S. spends an average of more than one billion dollars on snow removal each year (Zynda, 2016). Despite technological advances and the institution of routine winter road maintenance, however, a big snow storm can still temporarily shut down a city or region because our way of life is completely dependent on snow-free conditions. Snow can clearly be inconvenient and even dangerous in extreme situations, but it can also be a chance to pause from our daily routines and appreciate the power of an accumulation of snow crystals just millimeters in diameter to influence our lives in such a big way.
An alternative to either removing snow or packing it down for transportation is to control where it is deposited in the first place. Covered bridges, rock tunnels, and snow sheds (shelters that protect sections of railroad tracks or roads from snow) are all methods of keeping snow off roadways and railroads.
For example, the trans-continental Central Pacific Railroad, which crosses Donner Pass in the Sierra Nevada mountains of California, faced extremely deep snow accumulations (greater than 40 feet!) and and avalanches, both of which closed the railroad and endangered the lives of the railroad crew and passengers.The solution was to build more than thirty-seven miles of snow sheds and avalanche-deflecting barriers. The snow sheds were innovative in that, rather than trying to block avalanches from reaching the tracks, they were designed to allow avalanches to pass over the top of them while the train could pass in safety inside.
View photographs of a wide variety of snow control structures at https://mearsandwilbur.com/structural_defenses.html.
The other type of snow control structure that is widely used is snow fencing, which protects roads, railroads, and buildings from blowing and drifting snow. Snow fences are placed upwind of the area to be protected, creating a barrier that causes wind to slow down and deposit snow on the downwind side of the fence. Because blowing snow is deposited in a drift immediately downwind of the fence, the wind no longer carries a large amount of blowing snow beyond the fence to the roadway or other structure located further downwind.
Snow fences cause snow to be deposited on their downwind side, reducing the amount of snow transported further downwind. Translation of French words in this diagram: Vent = wind, congere = drift, and couverture de neige = snowcover. Illustration by Pierre_cb from Wikimedia Commons (CC-BY-SA-3.0)
The idea of controlling the location of snow drifts through strategic placement of barriers is at least centuries old. Farmers planted rows of trees or shrubs perpendicular to the prevailing wind direction to protect structures or roadways downwind.
Snow control engineering expert Dr. Ron Tabler (2003) suggests that the widespread use of snow fences probably began with the construction of the railroads, because vehicles confined to tracks are not able to detour around snowdrifts, and once a snow trench was developed along the track, snow removal became difficult. Examples of some early snow fences in the United States were stone blocks placed upwind of railroad cuts during construction of the trans-continental railroad in 1868-1869, and six foot tall (approximately) wooden snow fences, some of which remain in place today, constructed by the Union Pacific Railroad in Wyoming in the late 1800s.
After cars became widespread, highway commissions and transportation departments realized how much they improved roadway safety and reduced costs association with winter road maintenance, and construction of snow fences expanded rapidly. Snow fences reduce the amount of plowing needed to keep roads clear of snow, and they greatly improve visibility during blizzards (Tabler, 2003).
Snow drift control methods, including snow fences, became an active area of engineering research beginning in the 1930s with F.A. Finney’s wind tunnel experiments (Finney, 1939) followed by an extensive U.S. Forest Service research program in the 1960s and 1970s. Snow fence design today incorporates research-based engineering practices such as using porous fencing material, which traps snow better than a solid fence; locating the fence far enough upwind to prevent the snow drift from landing on the roadway; ensuring the fence is long enough to prevent wind whipping around the ends from eroding the drift; and ensuring that it is tall enough that the resulting drift is able to hold the amount of blowing snow typical of the area in which the fence is located.
Buildings and Infrastructure
Northern peoples have long built shelters designed to withstand the rigors of the environment, including structures built of snow, most famously the Inuit “igloo.” Despite changes in building design and materials, snow still affects the construction and maintenance of structures in snowy environments.
Roofs can be designed to either hold or shed snow, and there are advantages and disadvantages to each approach. The ability of a roof to effectively shed or hold snow depends on a variety of factors including the strength and weight of the building materials used, how well insulated the building is (snow is more likely to stick on a warm roof than a cold roof), the pitch (angle) of the roof, and the amount and density of snow that the area receives.
Roofs designed to shed snow move it from where we don’t want it (on the roof) to places where we don’t mind it piling up on the ground. The type of materials needed in constructing a roof that sheds snow are typically less expensive than those needed to build a roof designed to hold snow. On the other hand, snow now sliding off of a roof can pose a safety hazard; so-called “roof avalanches” can be fatal for a person caught underneath.
Roofs designed to hold snow are flat or have snow guards (rails or spiky obstacles) attached to the surface. In order to withstand heavy snow loads, roofs that hold snow require the use of stronger, more expensive construction materials, but they are safer, because snow loads won’t avalanche off of the roof on people entering or leaving the building.
Roof design starts with an assessment of “ground snow load,” the weight of snow per unit of area on the ground, and adjusting it for the type of roof being built. Other engineering considerations include unbalanced snow loads due to asymmetrical roof designs and drifting due to wind, and the occurrence of rain, which can soak into the snow and make it heavier.
We might not think of it as snow control, but the design of roofs in areas where it snows (particularly in areas where it snows a lot), has evolved over time in a similar way to the design of structures for protecting roadway and railroads from accumulating snow.
Other Effects of Snow on Infrastructure
Snow loading on trees, especially when combined with ice and/or wind, can cause trees to fall, blocking roadways and damaging roofs. In icy and windy conditions, powerlines may also fall, causing power outages, which can be dangerous if people rely on electricity for heat.
Snow also has its benefits. Snow’s insulating capacity keeps the ground warm and protects underground and above ground water pipes from freezing. Cold weather and lack of snow constitute a recipe for frozen and burst water pipes. Just as residents of hurricane or earthquake-prone areas take safety precautions for those conditions, people who live in cold and snowy climates need to be prepared for such situations.