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Archived

Avalanche Forecast

Jan 7th, 2015–Jan 8th, 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

Triggered avalanches are unlikely, but areas of shallow wet snow are expected, especially on steeper southerly facing slopes exposed to direct sunshine.

Detailed Forecast

Another dry, sunny and warm day is expected Wednesday. Freezing levels should again exceed 10,000 feet and along with light winds, causing areas of wet surface snow. Clearing overnight Tuesday should allow for the recent rain soaked upper snow layers to drain further, consolidate and allow for a thin surface crust to form. 

While wet snow avalanches should be unlikely, some shallow surface wet snow may make it possible to initiate a small loose-wet slide on some steep, mostly southerly facing slopes during the warmest part of the day. Watch for areas where surface snow is becoming wet for more than the top few inches.

 

Snowpack Discussion

From 3 to over 7 inches of rain fell over the Cascade west slopes from Sunday night to Monday evening, following about 5-15 inches of snowfall prior to the change to rain. The heavy snowfall at Mt Baker, where temperatures remained cooler Sunday night and where significant new snow was received, produced widespread natural avalanches along the Shuksan Arm as seen and reported by ski area patrol Monday, with consistent crown depths of about 2 feet. NWAC observer, Jeff Hambleton on Tuesday, scouting the aftermath of the event, found evidence of widespread wet snow avalanches, both loose and slab in the Baker area. 

Few other observations have been received since the major warming and rain event.

This recent rain should have eliminated any layers of concern in the upper  snowpack, leaving behind wet but draining upper snow layers. The rain reached the elevations of the Cascade crest, thus essentially resetting the overall still shallow snowpack, leaving behind wet but draining upper snow layers.

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: All elevations.

Likelihood: Possible

Expected Size: 1 - 1