Avalanche Forecast
Issued: Jan 20th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
ahanna,
Avalanche Canada
Use caution in steep, convex terrain where lingering storm slabs may remain sensitive to human triggering. Avoid terrain traps that can amplify the consequences of even small avalanches.
Summary
Confidence
Weather Forecast
Monday night: Clear. Light southwest winds, moderate at ridgetop. Alpine low -6 C. Freezing level dropping to valley bottom.
Tuesday: Mostly cloudy with isolated flurries bringing up to 5 cm of new snow. Moderate southwest winds, strong at ridgetop. Alpine high of -3 C. Freezing level around 1400 m.
Wednesday: Broken cloud with isolated flurries bringing a trace of new snow. Light to moderate westerly winds, strong at ridgetop. Alpine high -2 C. Freezing level around 1400 m.
Thursday: Broken cloud with isolated flurries bringing a trace of new snow. Moderate west to southwest winds, strong at ridgetop. Alpine high 0 C. Freezing level around 1800 m.
Avalanche Summary
On Monday, natural storms slabs up to size 1.5 were observed in steep alpine terrain below cliffy headwalls in the Lizard range. One was triggered by a cornice fall.
Over the weekend, results from control work were also limited to size 1.5. On Friday, a natural storm slab cycle was observed size 1.5-2.5.
Snowpack Summary
A sun crust can be found at the surface on south facing aspects, with a thin fog crust near the surface elsewhere. Slight wind effect may be observed in exposed alpine features. After over 1 m of steady snowfall last week, the stout upper snowpack continues to settle in the mild temperatures.
Several crust layers exist in the mid snowpack as a result of previous warming and rain events. These have not been identified as bed surfaces or failure planes in recent avalanche activity.
The bottom 10-20 cm of the snowpack consists of faceted snow and decomposing crusts. Although inherently weak, this basal layer has not been an active avalanche problem in our region since the early season.
Terrain and Travel
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
- Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- Carefully evaluate big/extreme terrain features before committing to them, it may not be full "go" time yet.
Problems
Storm Slabs
Natural storm slab activity up to size 1.5 has been observed as recently as Monday in steep alpine terrain below rocky headwalls. Human triggering remains a possibility in steep, unsupported terrain.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 21st, 2020 5:00PM
