Avalanche Forecast

Wednesday Outlook

Moderate to locally heavy precipitation should continue Tuesday night for the south and central Washington Cascades as the axis of moisture shifts slightly south. Moderate cool easterly flow through the Cascade Passes on Tuesday has allowed for some wet snow and spotty freezing rain to mix in at times with plain old rain. Easterly flow will ease overnight and snow levels at Stevens and Snoqualmie Passes will begin to reflect free-air snow levels seen further to the west. In the same vein, the NE Cascades including Washington Pass will warm Tuesday night as warmer air pushes the snow-line up to into the 6000-7000 ft range by Wednesday morning. 

Another wave of moisture in SW flow will traverse across the area on Wednesday before the main frontal band associated with the deep upper level trough offshore begins to sag SE across the Cascades late Wednesday night. This will be a relative break compared to the heavy precipitation experienced Tuesday and Tuesday night. 

The avalanche hazard will have peaked for most areas Tuesday or Tuesday night.

Poor and generally wet snow conditions are expected Wednesday.  Loose wet avalanches are still possible in steeper terrain. The larger and more dangerous wet slab avalanches or even glide avalanches that release to ground over smooth rock bed surfaces are again possible in isolated areas on Wednesday. We want to specifically highlight the Mt. Baker region with a special avalanche bulletin for the continuing low-likelihood/high consequence glide avalanche possibility due to the conditions in that area. 

Remember that closed ski areas without avalanche mitigation are equivalent to backcountry terrain!  Also, numerous early season non-avalanche hazards exist for backcountry travelers such as open creeks and barely buried rocks and trees.  

Climatologically speaking, mid to late November is our wettest/stormiest period and mother nature is not disappointing.  Unfortunately this most recent round of wetness has mostly come in the form of rain with over 1-3 inches of water at most NWAC precipitation sites in just the last 12 hours!  

The caveat to the heavy rain seen on the west side of the Cascades included some mixing of wet snow and spotty freezing rain in the Cascade Passes and a few inches of snow in the northeast Cascades before warmer air moved in late Tuesday afternoon.  In the locations with the heaviest rain and warmest temperatures (Hurricane, Mt. Baker, Crystal, Mt. Hood), our robust early season snowdepths have taken a sharp nose dive, with up to 12 inches of settlement in 24 hours! 

Warming through the storm at different stations throughout the Cascades:

Observations

Both Mt. Baker pro-patrol and WSDOT avalanche professionals at Chinook Pass on Monday reported natural avalanche activity with storm slabs likely releasing during Sunday night's storm. 

Mt. Baker pro-patrol saw a very active day on Tuesday with numerous large glide avalanches releasing down to steep rock surfaces near and below 5000 feet in elevation.  Besides the glide avalanches, widespread natural loose wet activity ranging from small to large was observed on Shuskan Arm.