Archived

Avalanche Forecast

Jan 20th, 2016–Jan 21st, 2016

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

4: High

The avalanche danger rating below treeline will be high

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

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: South Coast.

Conditions are ripe for an impressive avalanche cycle. Thursday is a day to wait out the storm from a safe place.

Confidence

High

Weather Forecast

Tonight and Thursday: 30-50 cm of snow. The freezing level starts near 1000 m and rises to 1600-2000 m late in the day. Winds are strong from the South. Friday: A few flurries and a clearing trend. The freezing level dips slightly to 1500 m. Winds ease to light from the SW. Saturday: Cloudy with sunny breaks. The freezing level is around 1200 m and winds remain light from the W-SW.

Avalanche Summary

A fairly widespread natural avalanche cycle was reported below treeline on Tuesday. Numerous slab avalanches up to size 2 were observed, primarily on sun affected slopes. On Tuesday there was also an incident on Mount Chief Pascal. One person was partially buried after triggered a 60-80 cm deep slab on North aspect near treeline. Check the Mountain Information Network for photos and more information on this incident. Conditions are primed for a large and widespread natural avalanche cycle with the incoming storm on Thursday.

Snowpack Summary

30-40cm of fresh storm snow has buried the recently formed mid-January surface hoar layer. Below that are the two early-January interfaces down 50-80cm which are separated by around 5-10cm of snow and both consist of a sun crust on steep solar aspects and a layer of surface hoar on sheltered and shady slopes. Strong southeast through southwest winds have been loading lee features at treeline and in the alpine. The mid and lower snowpack is generally strong, with the exception of shallow snowpack areas that may be more faceted.

Avalanche Problems

Storm Slabs

Expect new touchy storm slabs to form with heavy loading from snow and wind on Thursday. Widespread loose wet sluffing in steep terrain below treeline is also likely.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Stick to non-avalanche terrain or small features with limited consequence.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely - Very Likely

Expected Size: 1 - 4

Persistent Slabs

Expect heavy loading from snow, rain, and wind to overload buried surface hoar, potentially creating very large avalanches. This problem has been most active on shady slopes near treeline.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Avoid exposure to overhead avalanche terrain, large avalanches may run further than expected. >

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Very Likely

Expected Size: 2 - 5