Whitehorse Climate Change Adaptation Plan - Yukon College

54
Community Adaptation Project
Impacts and Community Responses to Problematic Snowfall
Snow generally impacts the community in two ways: directly through the amount of snow
that falls or through the amount of water released when it melts. One example of problematic
snowmelt occurred in April 1952 when heavy snowmelt created flooding in city streets, causing
damage to basements and furnaces and decompressing wells. Other examples of the damage
caused by problematic snowmelt can be found under the section Impacts of Flooding. The
remainder of this section describes the impacts of snow itself.
Structural damage due to heavy snow loads occurred in April 1954 when a large snow-slide off
the roof of the Civic Center damaged a part of the building. The heavy snow load also forced
the walls out of line and destroyed the windows. The cost of the damage was about $3,000
($24,425.53, 2009 adjusted value). In October 1968, newly fallen snow caused a number of
motor vehicle accidents. The same conditions occurred again in November 1968, which was the
first time that the airport runways were closed due to heavily falling snow. In December 1980,
Whitehorse missed a record snowfall by only two inches (the record was set in 1967 with a
snowfall of 272 mm). Snow clearing crews worked non-stop on Christmas day to clear the road
to the hospital and the priority streets in the downtown area. Nine minor accidents occurred
regardless.
The late 1980s and 1990s are seemingly marked by a considerable change in the amount of
snowfall in the Whitehorse area. The record for snowfall was broken several times over this
period, causing localized damage around the city. For example, a significant amount of snow
fell on Whitehorse in September 1986, which far surpassed the normal monthly total snow
water equivalent for that month. The mix of snow and freezing rain created dangerous driving
conditions, compounded by driver error. In at least one case, a resident failed to properly clear
their vehicle windows and accidentally backed into another vehicle. In the case of this storm,
public warnings constituted the community response. City crews were unable to keep up with
the snow clearance levels that the storm demanded, which resulted in poor driving conditions
on the highway. City crews subsequently warned residents against using the highway unless
necessary. At this time, the highway to Carcross was still under construction which further
increased the infrastructure stress. The 1986 storm set a record for precipitation and 67.2 mm
of snow and rain accumulated. About 53.9 mm of precipitation fell in 4 days, 2.2 mm fell as rain,
and another 31.4 mm fell as snow.
In December 1991, the 1986 snowfall record was broken and 677 mm of snow accumulated.
The city experienced high snow fall again in 1992; the warm wet snowfall caused an afternoon
blackout for 1000 people living between McCrae and Teslin. Moist snow had fallen onto an
insulator, which then broke off an electrical pole near Miles Canyon, resulting in a short. A diesel
generator was used to provide power for the Teslin area until the damage could be repaired.
Three megawatts of power were lost in the blackout. In the same storm, the weight of 300 mm
of snow caved in the roof of a vehicle.
In February 1996, a combination of mild weather and high winds resulted in a heavy snowfall
that caused trees to snap and fall on power lines. Problems reportedly began at the Robinson
subdivision and then expanded to include Annie Lake, Cowley Creek and Horse Creek. Residents
became frustrated as they lost power. The damage was so extensive that ultimately the electric
company opted to wait for temperatures to rise to 5°C and melt the ice and snow along power
lines. As a result of this incident, Yukon Electrical installed a breaker that would allow isolation of
a particular subdivision in the event that repairs would have to be made. Breakers are standard
across the territory such that power outages due to repairs are limited to localized areas.