Avalanche Forecast

Another weather disturbance passing through Monday will bring another round of wind and light to moderate rain and snow to the Olympics. Snow levels are expected to oscillate around 4000 feet on Monday. 

New unstable storm layers from Sunday night and Monday should be found near or just below treeline with unstable slabs forming on open lee terrain near and above treeline. Avoid steep open slopes, slopes connected to steep open slopes above and lee slopes receiving wind deposited snow. 

Wet loose avalanches will be likely on steeper rain soaked slopes...and may entrain snow down to the crust from last week.  

Also watch for recently formed large cornices along ridges and give them a wide birth and safety margin. They may be weakened by the warmer temperatures and new loading.  

Recent Northwest Weather

An extended mild and dry period occurred the latter half of January generally forming a crust in all areas. Very cold weather followed in early February which produced light low density snowfall, near surface faceting, and faceting near and just above the crust.

An extended 2 week storm cycle wrapped last Monday night, capping off impressive amounts of some 6-7 feet of new snow with a rain event that reached to near 7000 feet in the Olympics. Much of the following week saw sunshine and some very mild temperatures Tuesday through Thursday. Colder air arrived Saturday along with gradually increasing ENE winds.  A stronger frontal system with increasing temperatures and wind was in progress Sunday afternoon. Significant snowpack settlement occurred through the week during the warm stretch.

Observations for Hurricane Ridge area

Following the storm cycle, the deep cold snow layers took a dramatic turn Monday in the near and below tree line zones as rain returned and fell through Monday night and quickly changed the recent low density dry snow to wet snow conditions.   Runnels were reported on a variety of aspects and elevations following the rain event.  There were many field reports in  the Hurricane Ridge area Tuesday through Friday giving evidence of widespread wet snow avalanches running on most steeper slopes and a variety of aspects. 

The latest observation on Friday, Feb 28th by NWAC pro observer Tyler Reid comes from Klahhane Ridge to the east of Hurricane where plenty of wet unconsolidated snow was found on solar aspects below tree line from 4400-5600 feet.  Some small surface hoar growth was noted in places. For pre-storm conditions from the area see this video from Friday.

On Saturday, NPS ranger and Tyler reported a very hard surface crust had formed as a result of the significantly colder overnight and early morning temperatures. New snow received Sunday afternoon may not be bonding well to this layer. 

The late January crust layer and associated weak layers of early February are now deeply buried by the storm cycle snow.  While they were producing areas of collapsing and large whumpfing in mid-late February, they have not been involved in any recent avalanche activity. While triggering a slide on this layer has become unlikely, we are still urging more conservative travel plans based on the premise that not enough information is known about this layer and a slide on that layer could be devastating. This will not be listed as an avalanche concern while more likely storm related concerns are present. 

The mid and base pack around the Hurricane Ridge area still consists of stable crusts and melt form layers from periods of warm weather earlier this winter. The exception will be in the below tree-line zone on solar aspects where rain and mild temperatures keep the shallow snowpack wet and unconsolidated.