Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
Recent Avalanches: There was a remote-triggered avalanche in the Placer River Valley yesterday on a small terrain feature. Last weekend, there were multiple human-triggered avalanches on different aspects and elevations, mostly above 1,500', many triggered remotely.
We've been discussing if and when we may see sun and warmer temperatures begin to affect the slab, absent any other weather inputs such as snow or wind. We may have begun to see that yesterday in the Placer Valley, where a group of snowmachiners remote-triggered a small avalanche, likely composed of last week's storm snow. For today, this may be more common at lower elevations with a southerly tilt, rather than near ridgetops where ambient air temperatures will struggle to see 20 degrees F today.
Most avalanches we've seen in the past week have been on the smaller side, but can still prove problematic in steep or consequential terrain. The storm last week that impacted our area fell on a very weak, faceted surface from sea level to ridgetops, and now we're dealing with a persistent slab avalanche problem. These are slow to heal and notorious for allowing multiple tracks on a slope before avalanching.
This tends to be the time of year when we start looking toward bigger and more remote objectives in our winter pursuits. However, with a persistent slab problem, it's hard to have an 'open season' mindset. If you're choosing to move into bigger, more consequential terrain today, stack the deck in your favor by looking for clean runouts and practicing safe travel habits on both the ascent and the descent. It's equally as likely to trigger a persistent slab avalanche setting a skin track as it is descending a slope.
Loose Avalanches: The calendar says we should be considering wet loose avalanches, but the thermometer suggests we're more likely to experience dry loose avalanches again today. Unseasonably cool temperatures look to keep the surface snow cold for at least another day. Sluffs continue to run fast and are gaining volume, particularly in steep, northerly terrain above 2,500. However, if you begin to see or initiate roller balls on southerly slopes late in the day, at any elevation, these could be enough to trigger a persistent slab avalanche, as discussed above.
(3/25/2026)
This avalanche was remote-triggered yesterday in the Placer River Valley. It's possible the sun is playing a role in forming more cohesive slabs in the absence of wind at lower elevations.
Photo: Anonymous