Avalanche Forecast

Light rain and snow should linger the longest for the north Cascades on Monday morning, followed by a drying and likely partial clearing trend late morning through the afternoon. Freezing levels will be on the mild side. 

A natural loose wet avalanche cycle should have occurred Sunday night in many elevations and areas. Loose wet avalanches will remain sensitive to human triggering on Monday. Loose wet slides should be small in size, but possible on any steep slope regardless of aspect near and below treeline. 

Shallow wind slab may be found on lee slopes above treeline, potentially extending into the near tree-line depending on the local rain/snow line. Approach lee slopes with caution near and above treeline on Monday, watching for signs of recent or active wind transport.  

Small avalanches may travel further than you expect due to the 1/5 crust providing a firm sliding surface, so avoid steep terrain exposed to terrain traps.

Shallow storm slabs will not be listed as an avalanche problem as they should be unlikely to trigger Monday, but they may exist in isolated areas especially near and above treeline and potentially triggered on very steep slopes.

In areas with less recent snow above the 1/5 crust such as White Pass and Crystal, the avalanche danger will be locally lower relative to the zone rating. 

Early season hazards still exist. Many creek beds have still not filled in for the winter.

On Sunday, light precipitation that began as light snow during the morning by mid-day had briefly mixed with freezing rain at lower elevations of Snoqualmie Pass and changed to freezing rain/ice pellets at Paradise on Mt. Rainier. Light snowfall accumulated at Mt. Baker and Stevens Pass through the afternoon. Winds were transporting new snow and building fresh but thin wind slab in the Mt. Baker area, near tree-line at Paradise in some near treeline areas of Snoqualmie Pass. Any new or recent snow overlies the 1/5 rain or freezing rain crust. 

Below the 1/5 crust, reports indicate a strong upper snowpack with no notable layers of concern and a multitude of crusts formed over the last two weeks. 

Observations

North

NWAC pro-observer Lee Lazzara was out in the Bagley Lakes area on Sunday.  Lee found gusty winds transporting new and recent snow onto various aspects and forming thin but sensitive wind slab through the early afternoon well down into the below treeline band. The 1/5 rain crust was ski supportable. Visibility was poor but glide cracks had re-opened on some steep rock faces due to the heavy rain event that ended Friday.  No new avalanche activity was observed. 

Central

NWAC professionals traveled in both the Snow Lake and Kendall Peak areas of Snoqualmie Pass on Sunday. Thin wind slab, up to 8" (20 cm), was building on a north aspect above Snow Lake at 4600 ft and reactive in column tests, failing on the 1/5 crust as of mid-day.  In the Kendall area, 1-4" of snow was reported above the 1/5 crust. Little active snow transport was observed to ridgecrest.  A thin rain or freezing rain surface crust was forming later in the day.  No new avalanche activity was observed.   

NWAC pro-observer Jeremy Allyn was in the Smithbrook/Rainy Pass area east of Stevens Pass on Sunday. About 3-4" of recent and new snow was well bonded to the 1/5 crust which was semi-ski supportable. Travel conditions were difficult. No new avalanche activity was observed. 

South

A professional in the Paradise area Sunday reported a switch form snow to freezing rain/ice pellets by late morning. This trend likely continued into Sunday afternoon as light to moderate precipitation produced no new snow at the Paradise weather station. As of mid-day Sunday, 4-6 inches of recent and new snow was well bonded to the 1/5 crust with a thin freezing rain crust noted at the surface. Some wind transport was occurring near treeline above 6000 feet due to moderate west winds. No new avalanche activity was observed.