Avalanche Forecast
Issued: Mar 13th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Wet, Persistent Slabs and Wind Slabs.
mark herbison,
Our danger ratings are for the highest level we expect to see over the course of the day. The heat and solar inputs will be the main factors for the increase in avalanche danger. Start early and end early, to take advantage of the overnight recovery.
Summary
Weather Forecast
Sunday will remain clear as the ridge of high pressure persists. Valley bottom temperatures will reach +12, while the freezing level rises to ~2500m. Alpine winds will increase to 30-60km/hr from the SW and will persist through Sunday. Solar input will pack a punch on steep southerly aspects by mid day.
Snowpack Summary
10-20cm recent snow remains preserved on Northerly aspects and low angle terrain, on steep solar aspects a surface crust has formed. Some recent wind effect at higher elevations that seems limited to ridge crests. Recent profiles show the Feb. 19 and Jan. 27 facets in the upper meter with hard to no results. Cornices are huge!
Avalanche Summary
A natural avalanche cycle up to size 2 occurred Saturday on solar aspects, typically originating from steep rocky terrain. We expect this trend to continue through Sunday as freezing levels remain high.
Earlier this week several large persistent slabs were reported in high north aspects and we assume these were triggered by large cornice falls.
Confidence
Problems
Loose Wet
This weekend will bring warm temps and a rise in freezing levels and solar input. We should see some over night crust recovery, but watch for solar effect as conditions can deteriorate quickly.
- Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.
- Avoid exposure to solar aspects overhead, large avalanches may reach the end of run out zones.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
We have had a few persistent slabs triggered by cornices (which are large) over the past few days, mainly on alpine N aspects. Increased solar input and high freezing levels could reawaken this problem.
- Pay attention to overhead hazards like cornices which could trigger the persistent slabs.
- Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
We suspect moderate winds have created isolated wind slabs on immediate lee slopes in the alpine. Though small in size, this problem could pose a significant hazard in the wrong terrain.
- Watch for pockets of windslab in steep alpine features.
Aspects: North, North East, East.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 14th, 2021 5:00PM
