Avalanche Forecast

A weak disturbance will move across the region Saturday, causing increasing NW winds and very light snow showers. The main impact of the weather Saturday is that any light snowfall may bury intact a variety of weak surface snow types formed this week under fair cold weather.

Moderate to strong NW ridge level winds may build new fresh wind slabs on lee slopes, near and especially above treeline. 

Local wind slabs from the recent easterly winds is also possible Saturday. This should be mainly on westerly aspects near ridges.

Watch for firmer wind transported snow on all aspects, mainly near and above treeline.

In the Cascades, the December 8th layer continues to round and gain strength and should be less sensitive to trigger. We don't have any direct evidence of this persistent weak layer in the Olympics and it won't be listed in this zone as an avalanche problem. Do head for lower angle slopes and ratchet back your plans if you experience collapsing or whumpfing or have evidence of this layer such as from snowpits.

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

The last storm cycle to affect the Olympics was from late Thursday, December 8th through Monday morning, December 12th. About 2.6 inches of water equivalent and about 3 feet of snow fell at Hurricane Ridge ending Monday morning Dec. 12th. 

Fair and cold weather this week has been interspersed with periods of moderate E-NE winds both Wednesday and again Friday. These winds were strong enough to build fresh wind slabs on more atypical SW-NW facing terrain, mainly near and above tree line.

There has been about 12 inches of snowpack settlement since the storm cycle ended, allowing underlying or storm snow related weak layers to stabilize. 

Several clear nights with light winds this week have allowed for weak surface snow development. On wind and sun sheltered terrain, extensive near surface faceted snow or surface hoar have formed this week and this may be an important weak layer if buried intact by the expected return of light snowfall Saturday.

A thin sun crust is likely to have formed on steeper southerly facing slopes, which also may be a future interface for avalanches when loaded with sufficient wind transported or future storm snow.

Recent Observations

A storm related avalanche cycle was seen December 8th-11th. Some avalanches released on a December 8th persistent weak layer in the Washington Cascades, though the presence of that layer has not been verified in the Olympics as yet. 

The NPS ranger at Hurricane Ridge indicated widespread natural slides had reached the road in many places by Sunday morning, likely releasing overnight during moderate to heavy snowfall.

There is a report via the NWAC Observations tab from Sunday of a triggered slab avalanche on a steep east slope apparently above Lake Angeles.

No recent direct observations have been received since Sunday.