ENVIRONMENT YUKON






Frozen

Snow accumulation

Significance

The accumulation of snow is determined through measuring the snow water equivalent at survey stations across Yukon. This is a measurement of the liquid water volume held within a snowpack that can be available when melted.

  • Larger snowpacks (with more water) contribute to an increased likelihood of higher spring flows . Therefore, measuring the snow accumulation through snow water equivalent is a major component of spring flood forecasting.
  • The size of snowpack can also influence the timing and severity of river ice break-up.
  • Larger snowpacks (deeper snow) act to further insulate the ground surface from cold winter air temperatures and can further promote permafrost thaw.
  • Many other processes also have the potential to be influenced by changes in snow water equivalent including wildfire risk, shifts in vegetation, soil thermal regimes, and transportation.
  • Warming spring air temperatures over the past several decades leads to earlier snowmelt, and this trend is expected to continue.
  • Climate change projections generally indicate an increase in winter precipitation over a shorter snowfall period, and a higher proportion of precipitation occurring as rainfall. These contradicting processes to snow accumulation may induce a complex response that may vary significantly by region and over time.
Wolf Creek snow survey.

What is happening?

There has been a significant increase in the snow water equivalent, ranging from increases of six to 10 per cent per decade, measured at six of the 14 long-term snow survey stations analysed. There are no stations with long-term records available in the far north of the territory. None of the sites measured showed significant decreasing trends.

The significant increase in snow accumulation in the last several decades indicates an increase in winter precipitation. Sites with increasing trends in snow over time occurred in the Mayo-Dawson region and towards the Yukon-B.C. border.

Figures 1-4: Snow accumulation in upper Yukon drainage

[[slider::./images/report-water-snow-accumulation-figure-1.png|./images/report-water-snow-accumulation-figure-2.png|./images/report-water-snow-accumulation-figure-3.png|./images/report-water-snow-accumulation-figure-4.png]]

  • The stations at both Log Cabin and Meadow Creek showed significant increasing trends in snow accumulation; these were +6 per cent and +7 per cent per decade, respectively.
Figures 5-6: Snow accumulation in Liard drainage

[[slider::./images/report-water-snow-accumulation-figure-5.png|./images/report-water-snow-accumulation-figure-6.png]]

  • The stations in the Liard drainage showed the most significant trends. Frances Creek station had a 10 per cent increase per decade and Watson Lake station had a six per cent increase per decade.
Figures 7-10: Snow accumulation in Central Yukon drainage

[[slider::./images/report-water-snow-accumulation-figure-7.png|./images/report-water-snow-accumulation-figure-8.png|./images/report-water-snow-accumulation-figure-9.png|./images/report-water-snow-accumulation-figure-10.png]]

  • There were no significant trends noted at any of the Central Yukon stations.
Figures 11-14: Snow accumulation in Lower Yukon – Peel drainage

[[slider::./images/report-water-snow-accumulation-figure-11.png|./images/report-water-snow-accumulation-figure-12.png|./images/report-water-snow-accumulation-figure-13.png|./images/report-water-snow-accumulation-figure-14.png]]

  • The stations at King Solomon Dome and May Airport both had significant increasing trends in snow accumulation of 6 per cent per decade.
Dog mushing in Ibex Valley. F. Mueller.

Taking action

The Department of Environment’s Water Resources staff continue to collect data, as do their partners in Yukon’s remote areas including private contractors and staff from the Department of Energy, Mines and Resources. Water Resources compiles and quality controls all snow accumulation data.

Snowmobiling at Fish Lake. Marten Berkman.

Data quality

  • Access archived snow survey bulletins:
    http://www.env.gov.yk.ca/air-water-waste/snow_survey.php
  • Current snow survey data from across Alaska and Yukon can be viewed on an interactive map made available through a United States Department of Agriculture webpage.
  • There are currently 52 snow survey stations located across Yukon, with an additional four in adjacent areas of Alaska and British Columbia that are used by Water Resources. Most areas of Yukon have good spatial coverage with the exception of the far north, where stations are sparse.

Further information

References

Helsel, D.R., D.K. Mueller and J.R. Slack. 2006. Computer Program for the Kendall Family of Trend Tests: U.S. Geological Survey Scientific Investigations Report 2005–5275. U.S. Geological Survey, Reston, Virginia, U.S.A. Available from http://pubs.usgs.gov/sir/2005/5275/pdf/sir2005-5275.pdf.