Avalanche Forecast
Issued: Apr 22nd, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs, Persistent Slabs and Deep Persistent Slabs.
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Avalanche Canada
Warming temperatures and forecast snow or rain will increase avalanche hazard.
Expect spring conditions at elevations up to around treeline, and solar aspects well into the alpine. Temperatures are rising which over time melts the strength out of the snow; avoid avalanche terrain if the sun pops out, during periods of heavy snow or rain, or if you observe (recent) avalanche activity.
Summary
Confidence
Avalanche Summary
No new reports of avalanches on Friday.
Thursday reports were primarily Loose Wet slides due to solar triggers, a couple of size 2 wind slab or storm slabs. Also on Thursday was this report (from inside Glacier Park) showing the April Fools Crust remains a concern
Snowpack Summary
Dry, powder snow remains at higher elevations on north-facing terrain. While multiple melt-freeze crusts or moist snow are found in the snowpack on steep solar slopes and at lower elevations.
A layer of surface hoar from March 31 persists down roughly 50 to 100 cm appears to be variable in its distribution. The surface hoar may be sitting above a crust on all but true north-facing slopes. Despite a decrease in avalanche activity on this layer, avalanche professionals continue to closely monitor it. Additionally there are similar crusts dating from April 7 and April 16 higher up in the snowpack with similar characteristics and concerns.
The mid-snowpack is strong. However, the November depth hoar remains at the base of the snowpack and remains a concern in rocky, shallow, variable depth snowpack areas at treeline and above.
Weather Summary
Saturday Overnight
Cloudy with flurries. Just a trace of snow. Light southwest ridgetop winds. Treeline temperatures around -5 C. Freezing level around 1500 to 1800 m.
Sunday
Cloudy with snow. Accumulations by the end of the day around 10 cm but as high as 15 cm. Moderate southwest winds. Treeline temperatures around zero and freezing level around 2000 m.
Monday
Warm overnight temperatures with freezing level only dropping to 1500m. Overnight another 5 to 10 cm of snow by Monday morning. Wind diminishing to light. Treeline temperatures around -3 and freezing level around 2000 m.
Tuesday
A mix of sun and cloud. Nil precipitation. Wind light southwest. Around -5 C at treeline with freezing level around 2000 m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.
- Be alert to conditions that change with elevation and sun exposure.
- Closely monitor how the new snow is bonding to the crust.
- Be carefull around freshly wind loaded features.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Problems
Storm Slabs
New storm slabs are possible at high elevations. Dial back your terrain choices if you encounter more than 20 to 30 cm of new snow. Watch for this snow sitting on a slippery crust on solar aspects. Watch for wind slabs on lee features, primarily at higher elevations where dry snow persists.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Warm temperatures and new snow may increase the sensitivity of this lingering problem. A layer buried on April 1, down roughly 50 to 100 cm from the surface, appears to be most reactive on solar tilted slopes where surface hoar may sit on a hard melt-freeze crust.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A weak layer of facets exists near the base of the snowpack. The likelihood of human triggering is low given the layer's depth.
Suspect terrain includes steep, shallow, and rocky terrain where the snowpack varies between thin and thick.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 23rd, 2023 4:00PM
