Avalanche Forecast

Issued: Mar 20th, 2019 3:54PM

The alpine rating is high, the treeline rating is high, and the below treeline rating is considerable. Known problems include Loose Wet and Persistent Slabs.

Avalanche Canada swerner, Avalanche Canada

Email
Persistent hot and sunny weather is driving the avalanche danger. Avoid avalanche terrain especially in the afternoon on sunny slopes when the danger is at its HIGHEST.

Summary

Confidence

Moderate -

Weather Forecast

THURSDAY: A mix of sun and cloud. Freezing levels 3200 m and alpine temperatures near +9 degrees. Ridgetop winds light from the southeast.FRIDAY: A mix of sun and cloud. Freezing levels 2900 m and alpine temperatures near +8 degrees. Ridgetop winds light from the southeast.SATURDAY: Cloudy with light precipitation falling as rain at treeline and below and snow in the alpine. Freezing levels 1800 m and alpine temperatures falling to +1 degree. Ridgetop winds light from the South.

Avalanche Summary

On Tuesday, a widespread natural loose wet and wet slab avalanche cycle occurred up to size 2.5. These avalanches were from sunny aspects (SE-SW) 1700-2000 m. Explosive controlled wet slab avalanches up to size 3 were also triggered on sunny aspects between 1900-2200 m. Continued warming and a lack of overnight re-freeze we expect to see natural avalanche activity to continue.

Snowpack Summary

Currently, solar aspects are showing signs of melt by day and a freeze by night. In some locations, sheltered northerly aspects have new surface hoar forming and variable wind effect remains on exposed slopes at treeline and in the alpine. The current snowpack is complex and with the continued warming and little overnight re-freeze the snowpack will continue to break down. The bigger questions are deeper in the snowpack. Two crusts exist in the upper snowpack and the bond of the overlying snow is most concerning with deteriorating. The first crust is down 20 to 30 cm and loose wet avalanches have slid on this interface. The deeper one down 60-95 cm has also been producing easy shears in test profiles and potentially just waiting for enough heat to penetrate and deteriorate before avalanches start failing on it, if they do? Its hard to say how many hot days and warm nights it will it take to wake up the more deeply buried weak layers.

Problems

Loose Wet

An icon showing Loose Wet
Loose wet activity is expected to continue on most aspects and elevations. Cornices are softening up and becoming weak. You don't want to be under or near one of these looming monsters when they fail.
Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.

Aspects: North East, East, South East, South, South West, West, North West.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
Warm temperatures are penetrating deeper into the snowpack and a cohesive slab now sits above a series of weak layers. Large slab avalanches are failing on sunny slopes with warming.
The likelihood of deep persistent slab avalanches will increase with each day of warm weather.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1.5 - 3

Valid until: Mar 21st, 2019 2:00PM

Login