Avalanche Forecast
Issued: Jan 31st, 2024 4:00PM
The alpine rating is Persistent Slabs, Deep Persistent Slabs and Loose Wet.
, the treeline rating is , and the below treeline rating is Known problems includeThe widespread avalanche cycle over the past 72 hours has slowed. One more day of elevated freezing levels on Thursday will mean having some patience until things cool off, which should happen on the weekend.
Summary
Confidence
No Rating
Avalanche Summary
Previous widespread avalanche activity has occurred over the past 72 hrs. This includes natural wet loose avalanches up to size two on all aspects below treeline and on some steep solar aspects at higher elevations, and natural and explosive triggered avalanches up to size 2.5 failing on various facet, crust and basal facet weak layers at treeline and above. Avalanche control on Mt. Field Wednesday did not produce many avalanches, and overall activity has slowed.
Snowpack Summary
Previous rain and current warm temperatures have soaked the snowpack up to 2200 m, with moist surface snow even higher. Strong SW winds are creating wind slabs in alpine/treeline areas. Jan 19 facets from the cold snap are 10-30 cm deep, with the Dec 31 surface hoar/sun crust 30-50 cm deep. Two crusts (Dec 22 and Dec 5) exist in the mid-pack up to 2300m. The lower snowpack comprises weak facets and depth hoar in most areas. Treeline snow depths range from 70 -120 cm.
Weather Summary
Thursday - Freezing levels 2300-2400m with decreasing SW winds and mainly cloudy.
Friday - Freezing levels 1800-2000m with light SW winds and some flurries
Saturday - Freezing levels near valley bottom with some light to moderate snow amounts and light NE winds
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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
Persistent Slabs
Recently formed slabs sit on facets produced during the January cold snap, and surface hoar/suncrust is found below these facets. This unstable combination has caused multiple avalanches over the last week. While the temperatures are warm, avalanches are still likely on this layer.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
The base of the snowpack consists of weak facets and depth hoar, and the overlying midpack and crusts continue to break down. Human and natural triggering of these basal facets in steep terrain, large planar slopes, and thin to thick areas remains elevated until things cool off.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
Previous rain to 2200 m and warm temperatures have saturated the snowpack below treeline. This problem will likely diminish and then disappear on the weekend.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Valid until: Feb 1st, 2024 4:00PM