Changes in snow

 

Snow patterns are changing. In fact, snow cover and snow water equivalent (the amount of seasonal snow accumulation) have decreased in most areas of Canada over the past 35 years. These trends are expected to continue in the future.

Snow concepts

Snow can be discussed in many ways, including:

  • snow cover extent: the area of land covered by snow
  • snow cover duration: the number of days in the year with snow cover, from onset (first snowfall) in the fall to melt in the spring
  • snow water equivalent: the depth of water that would result if a given mass of snow on the ground were to melt at once. It is the volume of water available for melt in the spring. Snow water equivalent results from the seasonal accumulation of snowfall events.

Changes in any of these aspects of snow can be compared to a specific reference period. A reference period helps us measure change over time.

Patterns of snow change in Canada

Overall, snow cover duration has decreased across most of Canada over recent decades.  The number of days per season with snow cover has decreased by 5% to 10% per decade across most of Canada and during most seasons from 1981 to 2015. These decreases are due to later snow cover onset in the fall and earlier snow melt in the spring as a result of warming trends across most of Canada. This warming is projected to continue, with decreasing snow cover duration across all of Canada in fall and spring.

Snow water equivalent decreased by 5% to 10% across much of Canada from 1981 to 2015. Areas with declining snow water equivalent include the Maritimes, southern Ontario and northern Canada. Snow water equivalent increased in some areas of Canada including southern Saskatchewan, and parts of Alberta and British Columbia.

Significant reductions in snow water equivalent are projected across southern Canada in the future, with decreases of 5% to 10% per decade by 2050. The Maritimes and British Columbia are expected to experience the greatest changes.

Find snow data and other related resources in the library of climate resources.

Impacts of changing snow

In northern Canada, changes in winter snow conditions can impact wildlife habitat, overland travel, and access to food sources. This has an impact on traditional activities such as hunting, trapping and harvesting. These disruptions of traditional Indigenous and northern activities can lead to loss of culture, mental health impacts and food insecurity.

Changes in patterns of seasonal snow accumulation in Canada also pose risks for infrastructure. For example, increased winter precipitation during a shorter snow accumulation period can increase the potential of roof collapse.

Areas of Canada that experience significant decreases in snow water equivalent may see a decrease in water availability. This can impact agricultural production and increase the risk of forest fires. Winter recreation industries like skiing and snowmobiling could also suffer from reduced snow accumulation and warmer temperatures.

Adapting to changing snow

The Standards Council of Canada has developed a new standard for managing changing snow load risks for buildings in northern Canada.

In southern Canada, ski resorts are starting to assess climate change impacts and adaptation options. Some ski resorts are increasing snow making capacity and diversifying their activities, to support year-round tourism.

Related links

Sources
  • Derksen, C., Burgess, D., Duguay, C., Howell, S., Mudryk, L., Smith, S., Thackeray, C. and Kirchmeier-Young, M. 2018. Changes in snow, ice, and permafrost across Canada; Chapter 5 in Canada’s Changing Climate Report, (ed.) E. Bush and D.S. Lemmen. Ottawa, ON: Government of Canada.
  • Government of Canada. 2016. Canada's Marine Coasts in a Changing Climate. Government of Canada.
  • Intergovernmental Panel on Climate Change. 2012. Managing the Risks of Extreme events and Disasters to Advance Climate Change Adaptation: Special Report of the Intergovernmental Panel on Climate Change.
  • Palko, K. and Lemmen, D.S. 2017. Climate risks and adaptation practices for the Canadian transportation sector 2016. Ottawa, ON: Government of Canada.
  • Vincent, L. A., Zhang, X., Brown, R. D., Feng, Y., Mekis, E., Milewska, E. J., ... & Wang, X. L. “Observed trends in Canada’s climate and influence of low-frequency variability modes.” Journal of Climate 28, 11 (2015): 4545-4560.
  • Warren, F. J, and Lemmen, D. S. 2014. Canada in a Changing Climate: Sector Perspectives on Impacts and Adaptation. Ottawa, ON: Government of Canada.
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