Avalanche Forecast
Issued: Dec 25th, 2019 10:00AM
The alpine rating is , the treeline rating is , and the below treeline rating is
NWAC,
Northwest Avalanche Center
Sensitive weak layers may persist at high elevations, underneath last week’s storm snow. If you feel collapses, hear whumpfing or see evidence of avalanches, use caution on terrain connected to slopes steep enough to slide. Watch for low snow coverage and ground hazards at low and mid elevations.
Summary
Discussion
We received a public observation of a snowmobile triggered slab avalanche SE of Darland Mt on a NE aspect around 6600’ (photo below). The avalanche was triggered on Saturday afternoon. No one was buried or injured. Snow depths averaged around 4 ft. in this area.
The avalanche danger is trending down since the very large storm December 18-21. Recent storm snow instabilities at upper elevations are healing. However, persistent weak layers can remain sensitive to human triggering well after a storm. Without more direct evidence, you’ll have to tread carefully in terrain connected to slopes steep enough to slide. Persistent slab avalanches can break in surprising ways and can be triggered remotely or from low angled slopes.
The Darland Mt observation also helps us paint a picture of the rain/snow-line following the recent atmospheric river event. Rain likely reached at least 6000’ for much of the zone with remote weather stations showing a decrease in total snow depths due to a sustained period of rain and above freezing temperatures on the back end of the multi-day event.
At low and mid elevations, exposed or shallowly buried ground hazards, like rocks, stumps, and creeks can amplify the consequences of even a small avalanche.
If you’re out testing new holiday gear remember to submit an observation! The easiest way to post a photo!
Forecast Schedule and No Rating definition
At this time, we do not have enough specific snowpack information to issue an avalanche hazard rating for the East South zone. However, even when No Rating is applied, applicable avalanche conditions and backcountry travel advice will be provided throughout the season. When weather systems produce very dangerous avalanche conditions in adjacent zones, NWAC will issue an avalanche warning for this zone as well.
Snowpack Discussion
New Regional Synopsis coming soon. We update the Regional Synopsis every Thursday at 6 pm.
Valid until: Dec 26th, 2019 10:00AM
