Issued: Apr 1st, 2023 4:00PM
The alpine rating is Storm Slabs and Deep Persistent Slabs., the treeline rating is , and the below treeline rating is Known problems include
Give the storm snow another day to settle before venturing into larger or more committing terrain. Saturday's storm dropped variable amounts of snow across the region, and spotty spring squalls will continue for a few days, so observe your local conditions and let that inform your terrain choices.
On Saturday, northeast of Clearwater, several small (size 1) rider triggered storm slab avalanches were reported on steep rolls.
East of Revelstoke, explosives avalanche control produced a few small to large avalanches (size 1.5-2) in steep, north facing alpine terrain.
In neighboring Glacier National Park, several large (size 2-2.5), loose avalanches were reported in steep alpine chutes. They started in drier snow, and entrained wet snow as they ran below treeline.
On Thursday, north of Revelstoke, a large (size 2), naturally triggered, deep persistent slab avalanche was reported. It occurred on a steep, north facing slope in the alpine, below a large cliff face, and it is possible that it was triggered by a cornice fall.
10-25 cm of recent snow sits over a thin crust on steep slopes facing the sun right up into the alpine. Moderate southwest wind may have formed deeper deposits of snow on leeward slopes. On high, north-facing terrain, wind slabs may sit over facets and surface hoar.
The mid-snowpack is generally strong but the lower snowpack is a different story. The November facets are still prominent at the base of the snowpack. This layer remains a concern in rocky, shallow, or thin to thick snowpack areas at treeline and above.
Following Saturday's storm, a generally convective weather pattern will mean that the next few days will have spotty areas of cloud and light snowfall, or quick bursts of intense snowfall, but it also might be sunny, and everything could change at the drop of a hat.
Cloudy, spotty clear areas. Trace of snow expected. Moderate localized flurries bringing up to 5 cm in isolated locations. Light southwest ridgetop wind, possibly moderate at high elevations. Freezing level at valley bottom, treeline low around -9°C.
Mostly cloudy, possibly clear in the southeast corner of the forecast area. Trace of snow expected. Moderate localized flurries bringing up to 5 cm in isolated locations. Very light variable ridgetop wind. Freezing level rising to around 1300m. Treeline high around -5°C.
Mostly cloudy. Possible trace of snow expected. Up to 5cm in isolated areas. Light northwest ridgetop wind. Freezing level at valley bottom overnight, rising to around 1300m.
Mostly Sunny. Possible trace of snow expected. Up to 5cm in isolated areas. Light north or northwest ridgetop wind. Freezing level at valley bottom overnight, rising to around 1500m.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Keep in mind the crust offers an excellent bed surface for avalanches.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Saturday's storm brought 10-15 cm of new snow to most of the region, with isolated areas getting 25-35cm.
Moderate southwest wind may have formed deeper, more reactive deposits of snow on leeward slopes.
Due to the recent warm and sunny weather, a thin crust formed on steep slopes facing the sun right up into the alpine. Avalanches are more likely on slopes where the new snow is sitting on top of this crust.
Aspects: All aspects.
Elevations: All elevations.
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 for human triggering includes steep, shallow, and rocky terrain where the snowpack transitions from thin to thick.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Valid until: Apr 2nd, 2023 4:00PM