Avalanche Forecast
Issued: Jan 29th, 2024 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Wet, Persistent Slabs and Deep Persistent Slabs.
AB,
Avalanche Canada
A widespread avalanche cycle was observed Monday with numerous avalanches up to size 2.5, having occurred today near highway 93N. Freezing levels will peak late tonight, raising the avalanche danger to high at all elevations into Tuesday. Avoid avalanche terrain.
Summary
Confidence
Moderate
Avalanche Summary
Forecasters at Bow Summit today observed a widespread cycle at all aspects and elevations. Deep persistent and persistent slabs at treeline and in the alpine up to size 2.5. Loose wet avalanches were observed at treeline and below treeline up to size 1.
Also, during an avalanche control run on the Sunshine Road, avalanches up to size 2.5 were triggered with explosives from a helicopter. The slides were thin (~30cm thick) but released on the ground.
Snowpack Summary
Rain has saturated the snowpack up to 1900 meters and wind has created windslabs in most alpine/treeline areas. These slabs are releasing on two weak layers in the upper snowpack: 1) facets from the cold snap 10-30cm deep, and 2) surface hoar or sun crust below the facets 30-50cm deep. The lower snowpack is comprised of weak facets and depth hoar. Overall this is a weak snowpack that is untrustworthy.
Weather Summary
The next pulse of moisture comes through on Tuesday although not much precipitation is expected, less than 3 cm. Freezing levels fall slightly over all areas to a range of 2100-2400 m. Ridgetop winds remain strong to extreme from the southwest.
Tuesday evening as the winds taper and temperatures cool off, there is the potential for an inversion to set up Wednesday.
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Terrain and Travel Advice
- Avoid areas where the snow feels stiff and/or slabby.
- The likelihood of deep persistent slab avalanches will increase with each day of warm weather.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Problems
Loose Wet
Rain to 1900 m and warm temperatures have saturated the snowpack below treeline, and this has resulted in widespread wet loose avalanches happening in gullies. The snowpack below treeline will be weak and saturated until temperatures cool days from now.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Persistent Slabs
Recently formed windslabs sit on facets produced during the cold snap, as well as surface hoar/suncrust found below these facets. This is an unstable combination and we've seen evidence of multiple avalanches on this layer over the last week. Avoid steep, open slopes until it cools off again.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
The base of the snowpack consists of weak facets, depth hoar, and the overlying crust in the midpack continues to break down. Use caution in steep terrain, large planar slopes, and thin to thick areas where initiating these slabs would be more likely.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 30th, 2024 4:00PM
