Avalanche Forecast

Further cooling overnight Saturday and Sunday with a weak system, giving a chance of light snowfall in the south areas along with light winds, should all lead to an overall stabilizing snowpack. The main concern are areas of shallow wind slabs on lee slopes near ridges. Any previously wet or moist surface snow should have formed a strengthening crust by Sunday, locally decreasing danger. Further continued snowpack settlement should also allow for an improving trend.

Continued cautious routefinding and conservative decision-making remain the proper travel advice, until the persistent slab problems can be ruled out. 

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 of the WA Cascades as well as most areas to our north where Avalanche Canada is highlighting these layers throughout B.C.

A progressive weather pattern this week added about 1-4 over feet of snowfall to the east slope zones. Temperatures warmed above freezing to near or above 6000 feet along the east slopes during the day Thursday. WSW ridgetop winds stayed strong during storms at Mission Ridge as 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 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 guides travelling adjacent to Delancey Ridge this Friday, saw widespread evidence of the recent natural cycle, with numerous crowns visible throughout the region. Many crowns were estimated to be about 1 meter (3 ft.)

With the recent precipitation and warming temperatures experienced late this week, Thursday and Friday, it remains an uncertainty about just how sensitive the persistent layer currently is. It seems likely there are warring factions working to in opposition with a new moist or denser slab adding stress to that layer, while overall snowpack settlement works to stabilize that layer. Best to treat this as a real threat in tour planning and err on the side of caution.