Avalanche Forecast
Issued: Apr 7th, 2015 11:00AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Wet.
NWAC,
Northwest Avalanche Center
Due to a fair amount of uncertainty with the weather forecast, a moderate hazard rating will be forecast above treeline, however watch for local areas that have received greater recent snowfall where a locally greater danger may exist.
Summary
Detailed Forecast
Showers should end by Wednesday with clearing skies, light winds and relatively cool temperatures. Recent shallow snow may have only amounted to a few to several inches over the past few days, but in some areas near and above treeline there may be slightly more recent snow. Due to the showery nature of the expected precipitation, a fair amount of uncertainty is expected with the subsequent hazard forecast. A moderate hazard rating will be maintained above treeline for any new storm snow problems. However, in areas that receive little or no recent snowfall, expect a lower local avalanche danger than the regional forecast.
It's April, so be aware of the increased solar input reaching more aspects and affecting the snow surface quickly. Loose wet avalanches involving shallow amounts of recent storm snow will be possible, especially during sunbreaks and in the afternoon.
Due to the continued cool weather, cornices won't be listed as an avalanche problem either, however use caution on slopes below cornices and on ridges where it can be hard to know if a cornice is present.
Snowpack Discussion
The recent active weather since about mid March onward has brought periodic light snowfalls east of the crest and allowed general snowpack consolidation and stabilization.
A TAY report from Mt. Stuart Thursday, reported 6-12" of unconsolidated snow even on solar aspects above treeline, likely a benefactor of Tuesday night's convergence zone. NWAC observer Jeremy Allyn was in the Washington Pass area over the Easter weekend and found a few inches of recent snow on a thick crust that needed additional loading to become problematic. Greater recent storm snow was being preserved west of Rainy Pass, where about 10 inches of great unconsolidated powder was being maintained on shaded terrain at higher elevations, providing a bit of welcoming powder skiing!
Snowdepths vary greatly across the east slopes with a regionally healthy snowpack in the northeast Cascades to bare solar and lower elevation slopes in the central and southeast Cascades. Many areas at lower elevations and further away from the Cascade crest do not have enough snow to cause an avalanche danger.
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: East, South East, South, South West, West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 8th, 2015 11:00AM
