Avalanche Forecast

In the northeast and centraleast Cascades, moderate snowfall Thursday night through Friday morning and a slow warming trend should gradually stress and load buried weak layers, potentially resulting in large and destructive avalanches. A natural avalanche cycle may occur Thursday night through Friday morning. The danger from storm and wind slab avalanches will begin high Friday morning, but should decrease as showers taper down Friday afternoon and temperatures cool in the near and above treeline zones.  

Travel in backcountry terrain is not recommended Friday due to these conditions. 

Natural wet loose avalanches are possible predominately below treeline Friday and mainly on steeper slopes where temperatures stay or rise above freezing. Be especially wary near terrain traps, where even a small avalanche could have unintended consequences. Loose wet avalanches may entrain a considerable amount of storm snow, even at low elevations. 

The danger should be lower in the southeast Cascades, where less recent snowfall was received. 

Weather

Two fair weather periods earlier this month allowed surface hoar and near surface faceting to occur. These persistent weak layers were buried intact on Jan 3rd and 11th and have been reported through Monday from the Methow, the Icicle Creek area, the Blewett Pass area, the Nason Ridge area and the Chiwaukum range east of Stevens Pass. It's safe to say this layer is extensive throughout the east slopes.

A progressive weather pattern this week added about .5-1 feet of snowfall to the east slopes from about Friday to Sunday. Only a few inches of additional snowfall accumulated with a weather system that passed through Oregon Tuesday and Tuesday night. A warm front brought light to moderate amounts of new snow through Thursday morning, with up to 10 to 14 inches of new snow seen at the Hart's Pass snotel and Holden Village respectively, with about 6 inches at Mission Ridge. Temperatures warmed up above freezing along the lower east slopes during the day Thursday. WSW ridgetop winds stayed strong at Mission all well. 

Snow and Avalanche Observations

NWAC pro observer Jeff Ward on Sunday found the reactive persistent weak layer on shaded slopes up to about 5000 feet in the Early Winters drainage. A video by Jeff shows a similar persistent weak layer and a remotely triggered avalanche in the Icicle Creek Drainage near Leavenworth on Monday.

On Sunday the observer at the Scottish Lake High Camp in the Chiwaukums reported a natural 12 inch slab release on a southerly aspect around 5000 feet and easily identified two buried surface hoar layers in snowpits on a north-northwest slope at 5500 feet.

On Monday NWAC pro observer Tom Curtis was on Diamond Head near Blewett Pass in the 4-6000 foot range and found a persistent weak layer at 30-35 cm on north to east aspects with propagation indicated via PST and ECT tests. Tom's video is here.

NCMG on Monday found several persistent weak layers near Goat Peak at 6400' on a north aspect, reactive to column test and sensitive to human triggering.  

Remotely triggered avalanches on persistent weak layers were reported in TAY in the Mission Ridge area Monday. 

NWAC pro observer Tom Curtis visited the Rainy Creek drainage of the central east zone (near Jove Peak) Tuesday and traveled from 2000-5800 feet and did not find any signs of lingering persistent weak layers.

NCMG found touchy conditions below treeline near Delancey Ridge Friday on moderate slopes, with sensitive slabs releasing on the Jan 11th weak layer about 60 cm down. They also heard natural avalanches in their general vicinity.