Persistent Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
Recent Avalanches: There were several human triggered avalanches reported on Thursday including one in Todd’s Bowl where a dry loose avalanche stepped down to a deeper weak layer resulting in a large avalanche. Multiple natural avalanches around 1’ deep released in Portage, Placer Valley, and Whittier as well as Seattle Ridge and Lynx Creek. These occurred at all elevations with some releasing in the afternoon when temperatures peaked.
The recent increase in avalanche activity is telling us that weak layers buried in the snow are still an issue. The Todd’s Bowl avalanche is a reminder that weak layers around 2' deep may start waking up. This is a possible scenario where dry or wet loose avalanches have the potential to trigger a larger avalanche on these weak layers with higher consequences. There is also a weak layer buried around 1’ deep that is more likely to be triggered at upper elevations on wind loaded slopes.
This same weak layer is more widespread in Portage, Placer Valley, and Whittier and can be found at all elevations and mountain aspects making these areas more dangerous. These also have the potential to trigger deeper weak layers as well as in the Girdwood Valley where the snowpack structure is weaker.
Take some time to evaluate how easy the new snow could slide on test slopes and be aware that snow tests may be unreliable with this type of problem. Safe travel protocols are essential such as exposing one person in steep terrain and using safe spots that are out of the potential avalanche paths. With a lot going on, you can always choose more conservative objectives.
As temperatures creep up cornices may start falling off of ridgelines possibly triggering avalanches above you. Try not to spend time under them. Stay off of cornices on ridgelines so your weight is not responsible for releasing these huge chunks of snow and triggering a large avalanche on people below you.
(4/9/2026)
View of the avalanche on Todd's Bowl where a dry loose stepped down to a deep weak layer.