Avalanche Forecast
Issued: Feb 15th, 2015 10:00AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Wet.
NWAC,
Northwest Avalanche Center
The main problem to watch for east of the crest on Monday should be possible loose wet avalanches.
Summary
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, warm weather in the Olympics and Cascades Monday and early next week.
The main problem to watch for east of the crest on Monday 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.
A litte rain and then warmer temperatures have been seen the past few days and today. Due to the ongoing warm weather the last snow may not be distinguishable from earlier snow on many slopes.
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.
NWAC pro-observer Jeff Ward has been at Hart's Pass the past couple days and reports overnight refreezing of surface snow then some small ski triggered loose wet avalanches on solar slopes.
NWAC pro-observer Tom Curtis was on Labyrinth Mountain up the Little Wenatchee drainage on Saturday and found a no signs of instability and little snow on south slopes below 5000 feet.
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.
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.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Feb 16th, 2015 10:00AM
