Avalanche Forecast

Archived

Jan 27th, 2018–Jan 28th, 2018

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Regions

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Significant snow accumulation throughout this storm cycle has developed conditions ripe for very large and destructive avalanches. Avoid terrain where avalanches may start, run, and stop until we exit this storm cycle. Avalanches may entrain significant amounts of snow and travel far into their runouts effecting traditional travel routes. Numerous hazards will challenge your ability to travel safely in the mountains Saturday.

Detailed Forecast

The avalanche danger will increase throughout the day Saturday. Warming air temperatures, an increase in wind, and light to moderate showers will combine to create very dangerous avalanche conditions. Very large and destructive avalanches may occur. These slides can travel significant distances that extend far into the runouts.

Avoid areas where avalanches can start, run, and stop including terrain above you. Use very wide safety margins if traveling in the backcountry Saturday. Avalanches may overrun traditional safer locations.

Cornices have grown extremely large throughout this storm cycle. Limit your exposure to overhead cornice hazard.

Snow conditions have changed significantly during this stormy period. Tree-well and snow immersion hazards are very dangerous. Keep communication with your partner at all times.

Snowpack Discussion

Snow continues to pile up in the Mt Baker backcountry. Generally 4 to 6 feet of snow now sits atop the most recent crust. Numerous subtle layers exist within the storm snow but they are generally gaining strength.

As of Friday afternoon, loose surface snow was reported around the Baker area along with shallow storm slabs.

Wind transportation of the most recent snow has been limited to higher elevations and exposed features in the terrain.

Poor visibility and frequent storm conditions have limited observations above treeline during this period.

Observations

NWAC Observer Lee Lazara was in the Glacier Creek area Friday. Lee reported shallow sensitive storm slabs even in thicker trees below treeline. Four feet of snow was observed over the 1/18 crust.

Wednesday, Mt Baker Pro Patrol reported a very active avalanche cycle was ongoing. There were large natural avalanches releasing from Shuksan Arm and all avalanche paths in area were sensitive to ski triggering with slabs of 2 ft or more running long distances.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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

Wind Slab avalanches are the 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.