Avalanche Forecast
Issued: Apr 19th, 2019 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Loose Dry and Loose Wet.
tim haggarty,
Parks Canada
A significant avalanche cycle is underway. Conservative terrain selection Saturday is essential. Avoiding avalanche terrain would be wise.
Summary
Weather Forecast
An additional 5 to 10 cm is expected overnight with rain at lower elevations until early hours Saturday as freezing levels drop to valley bottom. Clearing is expected west of the divide with some clouds and flurries potentially lingering to the East. Freezing levels reach around 2000m Saturday afternoon as moderate alpine winds back to light.
Snowpack Summary
Between 60-100 cm of snow has fallen in the last week with snowpack values reaching seasonal highs 2000m and above. Extreme west winds Wed and Fri created widespread windslabs in alpine areas and continued sluffing in steep terrain. Wet snow and weak crusts below 2000m with warm temps and 10-15mm of rain Friday.
Avalanche Summary
Poor visibility with rain below 2000m today. A Cycle of loose dry and loose wet avalanches out of steep terrain is evident below the low ceiling. One slab at approx 1900m on a N aspect stepped down twice to about 80 and 100cm evidence for the idea that N and E aspects were not affected by the significant warming cycle in March.
Confidence
Problems
Wind Slabs
Significant snowfall over the last week combined with two periods of strong to extreme wind has created widespread wind slabs in the alpine. Be wary of exposure to loaded slopes and fresh cornice growth at alpine elevations.
- Avoid steep lee and cross-loaded slopes
- New snow will require several days to settle and stabilize.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine.
Likelihood
Expected Size
Loose Dry
Deep, loose dry snow exists in the alpine. Saturday's moderate winds or solar inputs can be expected to generate sluffs in gullies and down steep alpine faces. These sluffs can easily trigger wind slabs as they impact snow slopes below.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
Rain below 2200m and warm temperatures weakened and broke down surface crusts adding a significant amount of heat to the snowpack Friday. It will not take much heating to weaken these crusts again on Saturday
- Use extra caution on slopes if the snow is moist or wet.
- If triggered, loose wet sluffs may step down to deeper layers resulting in larger avalanches.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Apr 20th, 2019 4:00PM
