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Archived

Avalanche Forecast

Mar 11th, 2015–Mar 12th, 2015
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
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
2: Moderate
The avalanche danger rating in the alpine will be moderate
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: Cascades - East.

Isolated loose wet snow avalanches should be possible on solar aspects above treeline, especially in the Mt Baker area where more recent snow is likely. 

Detailed Forecast

A few lingering showers early Thursday should quickly give way to sunshine and warming temperatures. In any areas where snow from late Wednesday and Wednesday night accumulated, the rising temperatures and sunshine may lead to isolated wet snow avalanches, mainly on steep southerly facing slopes above treeline. 

Elsewhere, there should be too little recent snow from Wednesday to cause a significant increase in danger. 

Due to the low snowpack, especially below treeline, watch for terrain hazards such as open creeks, partially covered rocks and vegetation. Many areas below treeline do not have enough snow (new or existing) to pose an avalanche hazard.

Snowpack Discussion

The last snowfall occurred near the end of February; the central and southeast Cascades received the most snow with 7 inches at Mission Ridge, and generally 2 or 3 inches fell around the northeast Cascades. For much of March, sunny and gradually warmer weather has occurred, helping to form strong melt-freeze surface snow.

The North Cascade Heli and Mountain Guides in the Washington Pass area over the weekend reported some cool snow on north to east slopes with numerous snowpack tests giving no results. Many slopes above treeline were quite wind and sun-affected, producing variable skiing conditions but no stability concerns. On a positive note, the snow study plot on a north aspect at 6600 ft above Varden Creek measured a snow depth of nearly two and a half meters! Avalanche professionals in the Washington area on Tuesday re-affirmed the overall low avalanche danger. 

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.

Aspects: South East, South, South West, West.

Elevations: Alpine.

Likelihood: Unlikely

Expected Size: 1 - 1