Avalog Join
Archived

Avalanche Forecast

Jan 15th, 2016–Jan 16th, 2016
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
4: High
The avalanche danger rating at treeline will be high
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Sea To Sky.

New snow will add to the size and reactivity of recently formed storm slabs. Very tricky conditions are expected on Saturday and conservative terrain selection is critical. In areas that get the most wind and new snow, the local hazard may be HIGH

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

The first in a series of storm systems will reach the region on Friday evening. 20-30cm of new snow is expected between Friday evening and Saturday evening. Freezing levels are expected to climb to around 1300m and winds are forecast to be moderate to strong from the southwest. The second storm system is expected to reach the region on Sunday and is forecast to bring another 20-30cm by Monday night. Freezing levels are expected to hover around 1500m and alpine winds should remain moderate to strong from the southwest. A bit of a break between storm systems is currently forecast for Monday with another storm pulse Monday night.

Avalanche Summary

On Thursday, natural avalanche activity up to size 2 was reported in the Pemberton area on north and east aspects.  These were 30cm thick slabs releasing on a layer of surface hoar and facets.  Explosives triggered a couple size 1.5 storm slabs in the Whistler area where the storm slab was only 10-20cm thick.  Natural and human-triggered avalanches are expected to increase in size and reactivity as the storm progresses over the weekend.

Snowpack Summary

The new snowfall will add to the 20-40cm of storm snow from earlier in the week. This storm slab is sitting above a widespread layer of surface hoar, facets, and/or sun crust on steep south aspects. 10-20 cm below this is a second buried weak layer of surface hoar and/or a crust. The mid and lower snowpack is generally strong, with the exception of shallower snowpack areas that may be more faceted. At lower treeline elevations recent rains have saturated the upper snowpack. At higher elevations moderate southerly winds have recently loaded lee features at treeline and in the alpine.

Avalanche Problems

Storm Slabs

Snowfall on Saturday will add to the existing storm slab which is typically 20-40cm thick and overlies a widespread layer of surface hoar. Strong SW winds will result in increased loading of leeward features.
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain. >The new snow will require several days to settle and stabilize. >

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1 - 4