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Archived

Avalanche Forecast

Jan 26th, 2015–Jan 27th, 2015
Alpine
1: Low
The avalanche danger rating in the alpine will be low
Treeline
1: Low
The avalanche danger rating at treeline will be low
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
1: Low
The avalanche danger rating in the alpine will be low
Treeline
1: Low
The avalanche danger rating at treeline will be low
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Stevens Pass.

Be aware of a slightly greater avalanche danger in steeper terrain and near terrain traps relating to wet avalanches.    

Detailed Forecast

Cooler temperatures with clouds and a few light showers are expected Tuesday. Only very light amounts of precipitation are expected, if any, and this should not change the overall low danger.

Generally avoid steep slopes, especially near terrain traps where you might be able to push off enough wet snow to start an avalanche large enough to take you for a ride.

Remember, due to the unseasonably low snowpack especially at lower elevations, numerous terrain hazards such as open creeks, partially covered rocks and vegetation are widespread.  

Snowpack Discussion

The most recent significant snow from one week ago was involved in generally small avalanches Friday and Friday night during periods of heavier rain. 48 hr storm totals through Sat AM for NWAC stations west of the crest were 1.5 to 3 inches of rain from Snoqualmie Pass and north and 0.25 - 1.5 inches south of Snoqualmie. Mt. Baker received the most precipitation and Crystal the least. High freezing levels along with plentiful sunshine were seen around the Northwest Sunday. Recent weather has caused significant settlement of the snowpack with the upper portion consisting of wet grains.  

Our NWAC pro-observers were at Stevens Pass for a class Tuesday, Jan. 20th  and found a potential persistent weak layer of 2 mm facets on the Jan 15th crust. Pro-observer Jeremy Allyn was in the Skyline area on Stevens on Sunday and found this layer under a settled and wet 45 cm of snow on Sunday. While this layer failed at a density change below the crust during snowpack tests, it did not seem likely to propagate. Professional ski patrol from Mt. Baker and Alpental saw little in the way of natural or explosive triggered avalanche activity over the weekend. 

West of the crest, the middle and lower snowpack should consist mostly of stable, rounded grains or melt forms and crusts from warm periods this winter.

Avalanche Problems

Loose Wet

Release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. They generally move slowly, but can contain enough mass to cause significant damage to trees, cars or buildings. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.

 

Travel when the snow surface is colder and stronger. Plan your trips to avoid crossing on or under very steep slopes in the afternoon. Move to colder, shadier slopes once the snow surface turns slushly. Avoid steep, sunlit slopes above terrain traps, cliffs areas and long sustained steep pitches.

 

Several loose wet avalanches, and lots of pinwheels and roller balls.

Loose wet avalanches occur where water is running through the snowpack, and release at or below the trigger point. Avoid terrain traps such as cliffs, gullies, or tree wells. Exit avalanche terrain when you see pinwheels, roller balls, a slushy surface, or during rain-on-snow events.

Elevations: Treeline, Below Treeline.

Likelihood: Unlikely

Expected Size: 1 - 1