With multiple warm days in a row, and high overnight freezing levels, it's more important than ever to start (and finish) your day early. Look for objectives on north facing terrain without cornices overhead, and plan your egress route carefully.
Summary
Confidence
Moderate - Confidence is due to a stable weather pattern with little change expected.
Weather Forecast
A ridge of high pressure, with sunny skies and high freezing levels is dominating the weather pattern this week.
Thursday night - Clear / light northeast wind / alpine low temperature near 5 / freezing level 3000 m
Friday - Sunny / light east wind / alpine high temperature near 7 / freezing level 3200 mÂ
Saturday - Sunny / light west wind / alpine high temperature near 8 / freezing level 3200 mÂ
Sunday - Mainly sunny with increasing cloud in the afternoon / light north wind / alpine high temperature near 6 / freezing level 3000 m
Avalanche Summary
There have been several size 1-2.5 natural and human triggered storm and wind slab avalanches reported over the past week. These were mainly on northerly aspects in the alpine and at treeline. There have also been several cornice failures, and wet loose avalanches reported.
Looking forward, wet loose avalanches and cornice failures are expected to continue with sun and warm temperatures. The likelihood and potential size of these increases when temperatures do not dip below freezing overnight, and avalanche activity will likely begin earlier in the day with each subsequent warm day.
Wind slabs may still be possible to trigger on high elevation north aspects.
Snowpack Summary
The snow surface may be a crust, but high freezing levels on Thursday night may mean that the snow surface does not freeze in some areas. Sunshine and rising freezing levels are expected to quickly soften any crusts, resulting in a moist or wet snow surface.
Cornices are large and looming along ridgelines. Their release is unpredictable but increases in likelihood with daytime warming, requiring a large berth if you're travelling above or below them, especially when temperatures remain above zero overnight.
Terrain and Travel
- The more the snowpack warms-up and weakens, the more conservative you`ll want to be with your terrain selection.
- Avoid exposure to sunny slopes, especially in the afternoon.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- Avoid areas with overhead hazard, especially solar aspects.
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
Problems
Loose Wet
The snow will quickly lose cohesion and become unstable with sun and warm temperatures.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Cornices are large and looming along many ridgelines. They grow increasingly unstable during periods of warming.
Aspects: North, North East, East, West, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 16th, 2021 4:00PM
