Avalanche Forecast
Issued: Mar 18th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
astclair,
Avalanche Canada
Clouds and cooler temperatures may temper day-time warming and decrease avalanche hazard. Low hazard doesn't mean no hazard. Watch for lingering wind-loaded pockets and minimize exposure to steep, sun-exposed slopes if clouds dissipate.
Summary
Confidence
Weather Forecast
Wednesday night: Mostly clear, light northeast wind, alpine temperature -13 C, freezing level at valley bottom.
Thursday: Increasing cloud, light east wind, alpine temperature -6 C, freezing level 1400 m.
Friday: Mix of sun and cloud, light west wind, alpine temperature -5 C, freezing level 1500 m.
Saturday: Increasing cloud, light southwest wind, alpine temperature -4 C, freezing level 1600 m.
Avalanche Summary
Over the past several days, avalanche activity was reported as natural loose dry or loose wet avalanches size 1-2 running in steep, sun-exposed terrain in the alpine. One large (size 2) slab avalanche released naturally as a result of strong solar radiation on a south aspect at 2500 m.
Reports from this weekend show several natural wind slab avalanches ranging in size from 1.5 to 3 running in the alpine on northeast, south and southeast aspects at treeline and in the alpine. There were also several cornice failures on northerly aspects to size 2.5.
The number of data sources for the region is diminishing. If you're out in the mountains, please share your observations via the Mountain Information Network. Heightened diligence and conservative risk management is recommended at this time.
Snowpack Summary
Moderate to strong winds have created widespread wind effect and formed wind slabs that may remain possible to trigger in isolated areas. With recent sun and relatively warm temperatures, expect to find either moist surface snow or crust on slopes facing the sun. 30-50 cm of new snow from last week may sit on a surface hoar layer and a sun crust on steep solar aspects.
A widespread weak layer of surface hoar buried at the end of February is 60-100 cm deep. Sheltered north, northeast, and east facing slopes near treeline are the most likely locations to find this layer. The last reported avalanche activity on this layer occurred March 8th. There is a low likelihood of triggering an avalanche on this layer, but the consequences of doing so would be high. Read more about surface hoar on our forecaster blog.
Terrain and Travel
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- Small avalanches can have serious consequences in extreme terrain. Carefully evaluate your line for wind slab hazard before you commit to it.
- Make observations and assess conditions continually as you travel.
Problems
Wind Slabs
Previous moderate to strong winds blowing from a variety of directions formed wind slabs that may remain possible to trigger in isolated areas. Evaluate steep, wind-loaded terrain near and above treeline. If clouds dissipate, surface snow and cornices may also warm and weaken.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 19th, 2020 5:00PM
