Avalanche Forecast

Archived

Feb 14th, 2015–Feb 15th, 2015

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

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Watch for possible loose wet snow avalanches mainly on solar slopes on Sunday east of the crest.

Detailed Forecast

An amplifying upper ridge over the US and BC coastal waters will dominate the weather the next few days. This will cause sunny, warmer weather in the Olympics and Cascades Sunday and early next week.

The main problem to watch for east of the crest should be possible loose wet avalanches. Watch for initial rollerballs or surface wet snow deeper than few inches. While this is expected mainly on solar slopes midday watch for it on other aspects as well. Overnight cooling and surface refreezing will limit this problem on non-solar slopes and during the night and morning hours.

As a result of the overall low snowpack, especially below treeline, watch for terrain hazards such as open creeks, partially covered rocks and vegetation.

Snowpack Discussion

Warm and wet southwest flow directed a series of fronts across the Northwest from about February 5th-10th. The east slopes had a variety of weather and snow conditions. The Harts Pass Snotel and the NWAC Washington Pass weather station's total snow gages indicated about a foot of snow. Other areas east of the crest had less snow or rain. Mild temperatures have been seen the past few days and today.

NWAC pro-observer Jeff Ward is at Hart's Pass and reports only some small loose wet avalanches the past couple days.

The North Cascade Guides reported a small wind slab remotely triggered from a shallow area near rocks with facets last Monday. So there is still variability east of the crest within the last week.

Regarding the potential January 15th persistent slab in the northeast Cascades zone; NWAC pro-observers and the North Cascade Guides the past couple weeks found the January 15th facet/crust layers at anywhere from 35 cm-1 m below the surface with the facets starting to turn to rounded grains and not reactive or not releasing in pit tests. So the January 15th facet/crust layers are stabilizing and becoming very unlikely for a human to trigger. A very large natural avalanche that may have run on this layer east of Washington Pass was likely tied to the heavier precipitation and warming during the February 5th-10th period.

Problems

Loose Wet

Loose Wet avalanches are the 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. 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.