Avalanche Forecast

The forecast for Friday is a more complex than usual.

An occluded front should cross the Northwest Thursday afternoon and evening. This should cause continued west to southwest winds and a few more inches of snow Friday morning. This should maintain similar conditions through Friday afternoon. Watch for wind slab on lee slopes mainly north to southeast aspects. Storm slab may be possible on more varied aspects. Less snow and lighter winds as well as continued low snow depths should cause less avalanche danger at lower elevations.

The complex part of the forecast comes Friday afternoon and evening which will be a period of rapid change. A very strong front is indicated to cross the Northwest on Friday night. Currently it looks like the strongest winds, heaviest rain or snow and main warming will hold off through Friday afternoon and then begin Friday evening. The avalanche danger should greatly increase Friday night. Beware that if this system and these changes arrive sooner the avalanche danger could rapidly increase Friday afternoon.

The last storm cycle was late last week. The most significant avalanches from that period were human triggered 1-1.5 foot wind or storm slab avalanches reported Saturday from Mt Herman near Mt Baker and from Chair Peak near Alpental.

Sunny weather with increasingly warm temperatures were seen Sunday and Monday which produced some small loose wet slides on solar aspects and crusts on more varied but not all aspects. Less warming was seen in the passes due to cooler easterly flow. 

Weak systems began to move to the Northwest about Tuesday with persisting cool offshore surface flow. This caused light rain or snow and a mix of precipitation in the passes.

A stronger system moved across the Northwest on Wednesday. Snowfall at NWAC sites near and west of the crest was in the 6-17 inch range with the most at Mt Baker. An overall cooling trend Tuesday and Wednesday helped to bond new snow to older or crusted surfaces from Sunday and Monday and built mostly favorable new snow profiles.

The most relevant available reports on Thursday are from the ski areas. In summary isolated or local small storm or wind slabs up to a about a foot were reported from Mt Baker, Stevens and Alpental on Thursday with the releases within the new snow and with generally favorable new snow profiles. Isolated shallow storm slab of only a couple inches was generally seen at Crystal. Reports confirmed that bonds were generally good to older or crusted surfaces from Sunday and Monday.

Mostly light snow showers with minor temperature changes on Thursday should be generally maintaining these conditions.

Reports also seem to indicate that hoar frost seen early in this week generally didn't survive the changes or is not reactive. Reports indicate generally stable crusts and melt forms in the mid and base pack in this area.