Avalanche Forecast

Here we go again! With another round of light to moderate snow forecast Saturday night, followed by perhaps a brief break Sunday morning and then with renewed snowfall Sunday afternoon, 24 hr snowfall totals for the Olympics along the west slopes through Sunday 4 pm should average 6-12 inches with snow levels remaining relatively stable. Moderate W-SW transport winds should ease Sunday afternoon.   

With this latest round of snowfall, we are betting that we have arrived at the breaking point where avalanche activity becomes widespread, with natural avalanches likely and human triggered very likely. Wind loading of lee slopes will push the avalanche danger to High near and above treeline, but expect sensitive conditions in all bands. 

Additional snowfall at more moderate temperatures will aid in a more uniform slab structure in the Hurricane Ridge area, potentially leading to storm slabs failing on weak persistent grain types formed prior to this storm cycle. Storm slabs that initially fail within the new storm snow may step down to these increasingly deeper layers. Remote triggering of avalanches is possible with this snowpack structure. Choose low angled terrain and avoid slopes connected to avalanche paths with wind loaded start zones.

Expect new wind slab near and above treeline especially on lee easterly aspects. Avoid all wind loaded terrain Sunday. 

Loose dry will not be listed as an avalanche problem, but in steep terrain lacking a slab structure, continue to watch for small loose dry avalanches near terrain traps like cliff bands where even small avalanches can have big consequences. 

With deep unconsolidated snow in many wind protected areas, there is an increased risk for tree well and snow immersion suffocation at this time. Ride or ski with a partner and keep them in sight at all times!

Even though the lower part of the below treeline band is filling in, watch for early season travel hazards such as barely covered rocks and open creeks.

Weather and Snowpack

An active and cool weather pattern has resulted in a snowy December thus far with the Hurricane Ridge NWAC station recording over 4 feet of snow, including 10 inches of new snow through Saturday morning. 

Cold and fair weather was in place midweek likely allowing near surface faceting and/or surface hoar to become widespread. Beginning Wednesday night and continuing through Thursday, considerable wind transport from easterly winds occurred near and above treeline. 

Beginning Thursday night and continuing on Friday, a switch to south-southwesterly winds occurred along with a moderate warming trend and light snowfall. 

Prior to this new snow, the snowpack in non-wind affected terrain was generally right side up with low density snow at the surface and no problematic layers in the lower snowpack. 

Recent Observations

Moderate easterly winds midweek likely built new wind slabs on lee aspects near and below treeline in the Hurricane Ridge area with plenty of low density of snow available for transport. A switch to light S-SW winds late this week may have begun to redistribute snow to more traditional aspects Friday. 

This redistribution of recent and new snow likely continued on Saturday. We don't have any snowpack observations identifying persistent weak layers in the Hurricane Ridge area so we have a large amount of uncertainty if new wind and storm slab avalanches will step down to deeper layers.