Avalanche Forecast

Rain is expected Saturday night with a lull in precipitation Sunday morning for the central and south Washington Cascades. Moderate to occasionally heavy rain should continue for the Mt. Baker area. By late morning precipitation should once again increase and the cold front should push through in the afternoon as snow levels  drop to 3500-4500 feet by 4 pm.  

Wet snow conditions will persist, maintaining the potential for glide avalanches on steep unsupported terrain features that may not have released during recent heavy rains. Much of the below treeline elevation band does not have enough snow cover to support an avalanche hazard. Loose wet avalanches will only be listed in the Mt. Baker zone, where there has been enough new snow to present a loose wet problem. Isolated pockets of wind slab may exist above treeline but will not be included in the problem set. 

Watch for the numerous travel hazards such as open creeks, barely buried rocks and trees, and glide cracks, creating poor and challenging travel conditions, especially below treeline. 

Remember that closed ski areas without avalanche mitigation are equivalent to backcountry terrain!  

New resources within your Avalanche Forecast this season! 

The Mountain Weather tab will take you to the most recently issued Mountain Weather Forecast. The Observations & Weather Data tab will allow an easy view of the various weather station graphs within your zone of interest and provide easy access to the most recent avalanche and snowpack observations. 

The great start of winter 2017/18 in the PNW has taken a recent hit as warm wet weather arrived Tuesday morning and lasted through Thanksgiving. Most areas along hte west slopes of the Cascades received 4-9 inches of rain since Tuesday morning, reaching well above the Cascade crest level. The warming and rain initially triggered numerous wet snow and glide avalanches earlier this week, mostly reported on Tuesday and Wednesday. Numerous size 2 avalanches occurred, especially on steep unsupported slopes and rock faces where many glide avalanches released. 

Rain has now melted significant snow with average snow depths decreasing about 35-60% since Monday! This has allowed much of the previously well snow covered terrain to open with many creeks and snow bridges re-appearing, especially near and below treeline. 

Cooling since Thursday with additional, mostly light precipitation, has begun to add some shallow new snow above the old wet snowpack. In the Mt Baker area, about 12 inches of new snow had accumulated as of Saturday morning.

Observations

A few NWAC observers began assessing the post deluge Friday, Nov 24, both in the Mt Baker and Alpental Valley backcountry. 

In the Baker region, the key takeaway is just how much the snow cover has diminished with travel becoming significantly more challenging and hazardous due to open creeks and shallow snow. Most of the observed recent wet snow or glide avalanches were estimated to be two or more days old. The most recent storm snow, up to about 6 inches, was reluctant to release on steep test slopes with storm layers appearing to rapidly settle with near freezing temperatures. No direct observations were made above treeline.

In the Alpental Valley, a similar story is told with evidence of numerous glide avalanche releases from steep unsupported terrain and rock faces. Travel conditions, especially below treeline, are now difficult with numerous early season challenges and hazards having quickly returned.