Avalanche Forecast
Regions: Cascades - North West.
Warm weather will create dangerous avalanche conditions throughout the area Saturday. Avoid steep open slopes at all elevations where you are likely to trigger avalanches. Natural large avalanches have occurred recently in the Baker area. Travel on lower angle terrain and use extra caution if traveling in areas where avalanches may run or stop.
Detailed Forecast
Warm weather and early morning rain/snow will maintain dangerous avalanche conditions in the Mt Baker area Saturday. Avalanche conditions will largely depend on precipitation type.
At elevations receiving snow, moderate winds combined with additional snow will continue to form Wind Slabs on a variety of aspects. Avoid slopes where winds are depositing snow such as below cornices, on snow drifts, or near uneven snow surfaces.
In areas where rain has fallen, stay off of steep slopes with wet surface snow. New roller balls and pinwheels are signs you are likely to trigger a Loose Wet avalanche. While Wet Slab avalanches are becoming less likely on Saturday, avoid steep open slopes during periods of intense precipitation when these slides are more likely to occur.
Large Cornices exists along ridgelines. Warming air temperatures and rain will make these massive blocks of snow more likely to fail. It is very difficult to predict when and where Cornices will fall. Avoid traveling on or below Cornices during this warm weekend.
Significant amounts of new snow have fallen in the Baker area this week. Recent large natural avalanches deserves respect. This is a time to keep terrain choices very conservative. Large terrain will produce large avalanches. Extra caution should be taken if traveling below large avalanche paths.
Snowpack Discussion
Mild wet weather changed snow surface conditions in the Mt Baker backcountry Friday. Below 5000 feet, above freezing temperatures and rain created moist to wet avalanche conditions. This was highlighted by a natural Loose Wet avalanche cycle on all aspects.
Above 5000 feet, warming temperatures stiffened surface snow causing Wind Slabs to become easier to trigger.
A few large natural Wet Slab and Wind Slab avalanches occurred during peak warming and precipitation Friday.
Across the area 2-3 feet of settle storm snow accumulated over the past week.
Observations
Mt Baker Ski Patrol reported rain to 5000 feet Friday with a natural loose wet avalanche cycle occurring in the adjacent backcountry terrain. They observed debris from larger slab avalanches on the Shuksan Arm and Mt Herman.
NWAC pro-observer Lee Lazzara traveled in the Canyon Creek area Thursday. Lee found 15-24 inches of recent snow over the 1/29 crust. Wind Slabs were noted in terrain near ridgeline but poor visibility limited observations near treeline.
An avalanche professional traveling in the Mt Baker backcountry Thursday reported up-side-down surface snow conditions. More than 3 feet of snow was observed over the 1/29 crust. Poor visibility limited observations in the area.
Avalanche Problems
Wind Slabs
Release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Wind Slabs form in specific areas, and are confined to lee and cross-loaded terrain features. They can be avoided by sticking to sheltered or wind-scoured areas..
Wind Slab avalanche. Winds blew from left to right. The area above the ridge has been scoured, and the snow drifted into a wind slab on the slope below.
Wind slabs can take up to a week to stabilize. They are confined to lee and cross-loaded terrain features and can be avoided by sticking to sheltered or wind scoured areas.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1
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: Likely
Expected Size: 1 - 1