Stevens Pass

Keep your terrain selection conservative Saturday: Human triggered slides are likely on wind loaded aspects near and above tree-line, which also happens to be the elevation bands with solid snowcover. Shower intensity and sunbreaks will locally mix in loose wet and storm slab avalanche potential. Choose more moderate and less wind affected terrain and safely enjoy a taste of winter. 

Cool mid-April storms in a snow starved season can be a recipe for accidents: Enjoy a taste of winter Saturday but keep your terrain selection conservative. Human triggered avalanches are likely on wind loaded aspects near and above tree-line. Shower intensity and sunbreaks will locally mix in loose wet and storm slab avalanche potential.  

A vigorous frontal system passing through Friday night will bring a sharp drop in snow levels by early Saturday morning.  Light and scattered post frontal showers Saturday morning should become more intense and widespread in the afternoon, including in a Puget Sound convergence zone near Stevens Pass.  

Despite the strong cooling trend that will help new storm snow bond well to Friday night's snowfall, moderate and consistent westerly transport winds will continue to load lee aspects near and above treeline throughout the day.

Also, periods of intense snowfall during heavier showers combined with subtle daytime warming may locally escalate the storm slab potential Saturday afternoon and evening, with storm slabs failing within the new snow or new graupel layers.

Even with the winter-like temperatures, mid-April sunbreaks in the late morning or mid-day can trigger loose wet avalanches involving the new storm snow on solar aspects.  

Cornices won't be highlighted as an avalanche problem due to the cool weather but use caution on slopes below cornices and on ridges where it can be hard to know if a large cornice is present.

A broad upper trough moved over the Northwest last weekend through early this week causing periods of light snow west of the crest at low snow levels. On Wednesday and Thursday, clear skies transitioned to scattered afternoon showers with light and spotty new accumulations. April freezing levels have been very low compared to most of the winter, averaging about 4-5000 feet thus far.

Backcountry reports from across the Cascades near and above treeline indicate cool, preserved snow on non-solar aspects with limited wind effects (see exception below), gradual settlement and generally good bonds to the previous crust.  On solar aspects, sun breaks have caused only small loose wet avalanches and crusts. Some large cornices continue to be reported along ridges especially in the north Cascades. 

A TAY report from Wednesday in Glacier Basin MRNP and NWAC observer Dallas Glass on the SW side of Mt. Rainier Thursday noted small and local wind slab lingering above treeline. 

Snowpack problems west of the crest should remain in the upper or surface layers. The mid and lower snowpack west of the crest consists of layers of stable consolidated rounded grains or melt forms and crusts from multiple warm periods this season. Many areas at lower elevations do not have enough snow to cause an avalanche danger.