Persistent Slabs
- Alta quota
- Limite del bosco
- Sotto il limite del bosco
- Probabilità
- Likely
- Dimensione
- 1.5–2.5
Recent Avalanches: Yesterday, there was a small wet slab avalanche observed on John Mtn that likely occurred on Sunday. Four large slab avalanches occurred on the west side of Butch Mountain on Thursday.A large avalanche was observed on the north aspect of Tri-Tip on Monday, which propagated widely across the slope and ran towards Tenderfoot.
The storm system in the past 24 hours mostly missed the Summit Lake area, with no new precipitation recorded at the SNOTEL site. However, this site can underrepresent some areas that typically get more snow, like Manitoba. So it is still worth keeping an eye out for new snow totals and potential for recently formed wind slab avalanches up to 1' deep at upper elevations.
Recently, there have been several large avalanches failing after wind loading events on Tri-Tip and Butch. We don't know exactly what the weak layer is for these avalanches, but it could be either large wind slabs or some kind of weak interface in the upper snowpack.
In addition to the recent activity, there are deeper weak layers in the Summit Lake snowpack that could cause much larger avalanches if they become reactive to the weight of a skier again. These layers were problematic early in the season and have been sitting at the base of the snowpack ever since. If you feel any collapsing or start to sink into the snow on skis or boots, this is a sign that deeper avalanches on buried weak layers are possible.
(4/23/2026)
A view of several of the large avalanches that we believe all occurred on April 22 on Butch Mountain. It was interesting that there were 4 large natural avalanches on this mountain in one day and no where else that we could see.