Avalanche Forecast
Issued: Apr 25th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Deep Persistent Slabs, Loose Wet and Cornices.
trettie,
Avalanche Canada
Be diligent in making ongoing assessments. This time of year conditions and hazard will vary greatly from one slope to another and can change quickly throughout the day.
If in doubt choose more conservative terrain.
Summary
Confidence
Avalanche Summary
Avalanche observations are limited this time of year but we are confident the likelihood of avalanches will increase with the high freezing levels in the forecast.
Please help out your fellow backcountry users by filling out a Mountain Information Network report.
Thanks for the great details in this MIN.
Snowpack Summary
In the alpine dry snow can still be found on north facing terrain. In the morning dry snow may be found on south facing terrain but it will quickly become moist when the sun pokes out. At treeline a crust over moist snow will likely be found in the morning but it will break down with day time warming. Below treeline the snowpack is diminishing , moist or wet snow will be found at this elevation.
A layer of surface hoar and a crust from March 31 persists down roughly 50 to 100 cm at treeline and above. This layer remains a concern on sheltered terrain at upper treeline where surface hoar may still exist. Additional crusts can be found in the upper snowpack.
The base of the snowpack in many areas is made up of facets and even depth hoar in shallow areas. As freezing levels rise this layer will pose a serious concern.
Weather Summary
Tuesday Night
Partly cloudy with up to 5 mm of precipitation expected, snow at treeline and above with rain below. Moderate westerly wind and Freezing levels falling to treeline.
Wednesday
A mix of sun and cloud with 5 to 15 mm of precipitation possible, rain at treeline and below with moist snow in the alpine. Moderate to strong westerly winds and freezing level rising to mountain tops or near mountain tops.
Thursday
Mostly sunny with no new precipitation expected. Moderate to strong northwest winds and freezing level rising to 2500 in the north and 3200 in the south.
Friday
Sunny with no new precipitation expected. Light to moderate westerly winds and freezing levels rising to 3000 in the north and 3500 in the south.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- The likelihood of deep persistent slab avalanches will increase with each day of warm weather.
- Keep in mind that wet avalanches can be destructive due to their high density.
- Avoid exposure to slopes that have cornices overhead.
- Avoid terrain traps where the consequence of any avalanche could be serious.
Problems
Deep Persistent Slabs
The base of the snowpack of made up of facets and even depth hoar in shallow snowpack areas. This layer could become rider triggerable as freezing levels rise and the snowpack weakens.
Further up in the snowpack a layer of facets, crust and surface hoar can be found. This layer will likely become more reactive as well. This layer is most concerning in the Selkirks.
Slab and loose avalanches as well as cornice falls have the potential to trigger these deeper layers.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
Rain, rising freezing levels and solar input will result in wet loose avalanches in steep terrain.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
As the freezing level rises and solar input increases the likelihood of natural cornice failures will also increase. Do not travel on cornices and avoid traveling on slopes with cornices above. Cornice falls can trigger large avalanches on the slope below.
Aspects: North, North East, East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 26th, 2023 4:00PM
