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West Slopes South - South of I-90 to Columbia River

Issued: 7:11 PM PST Sunday, February 4, 2018
by Dennis D'Amico

NWAC avalanche forecasts apply to backcountry avalanche terrain in the Olympics, Washington Cascades and Mt Hood area. These forecasts do not apply to developed ski areas, avalanche terrain affecting highways and higher terrain on the volcanic peaks above the Cascade crest level. 

Heightened avalanche conditions exist on slopes steeper than 35. Large and destructive Glide avalanches and cornice falls are possible where rain has saturated old snow. Avoid terrain with open cracks in the snow and overhung cornices near ridge lines.

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Avalanche Problems for Monday

Glidei

Glide avalanches occur when water lubricates the interface between the snowpack and the ground. These avalanches are difficult to predict and best managed by avoiding terrain below glide cracks.

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Loose Weti

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.

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Avalanche Summary:

Wet weather over the weekend created moist to wet surface snow conditions up to 6500 feet. A natural Loose Wet avalanche cycle occurred Friday and Saturday. Observers reported both natural cornice falls and glide avalanches. We’ve received minimal reports of Wet Slab avalanches. Poor visibility and stormy conditions have limited observations at higher elevations. Across the region rain totals averaged 1” during daylight hours on Sunday with 1.06” at Steven’s Pass, .95” at Snoqualmie Pass, and .88” at Paradise on Mt Rainier.

Observations

Stevens Pass

NWAC Avalanche Forecasters and observers noted numerous natural wet loose avalanches on all aspects Friday and Saturday. These avalanches ranged from small to large, with some travelling 1000 vertical feet.

Snoqualmie Pass

On Sunday NWAC observer, Matt Schonwald, found a saturated snowpack with rain water more than 2 feet below the snow surface. Alpental Ski Patrol reported audible cornices collapses along ridges in the Alpental Valley on Saturday. Both patrol and NWAC observers reported Glide avalanches, visible glide cracks, and many wet loose avalanches

South

Crystal Mountain Ski Patrol reported skier triggered wet loose avalanches in terrain with an uncompacted, backcountry-like snow on Saturday.

Forecast for Monday:

While avalanches will be difficult to trigger today, they could have serious consequences. Glide Avalanches and cornice falls could be big enough to bury or kill you.  Both of these types of avalanches form in specific types of terrain. The best way to stay safe is to avoid areas where these avalanches form and release. Watch out for slopes with visible glide cracks or where known rock slabs lie under the snowpack. Give yourself an extra wide margin of safety near ridges that could hold cornices, and avoid slopes with cornices overhead.

Many Loose Wet avalanches ran in the past couple days. This avalanche cycle is tapering off but is still possible today. While these avalanches may be the smallest and most predictable of today’s avalanche flavors, they could still be big enough to injure you. Avoid traveling through or above terrain that could increase the consequences of being caught in an avalanches such as or cliffs, gullies, or rocky slopes.

No Corresponding Mountain Weather Forecast Available

USE AT YOUR OWN RISK

This Backcountry Avalanche Forecast is provided in conjunction with the US Forest Service, and is intended for personal and recreational purposes only. Safe backcountry travel requires preparation and planning, and this information may be used for planning purposes but does not provide all the information necessary for backcountry travel. Advanced avalanche education is strongly encouraged.

The user acknowledges that it is impossible to accurately predict natural events such as avalanches in every instance, and the accuracy or reliability of the data provided here is not guaranteed in any way. This forecast describes general avalanche conditions and local variations will always occur. This forecast expires 24 hours after the posted time unless noted otherwise.