Avalanche Forecast
Regions: Snoqualmie Pass.
Watch for wet loose concerns mainly during the afternoon and on steeper solar slopes.
Detailed Forecast
A weak upper level shortwave should pass mainly into southern B.C. Friday, but will grace the northern Cascades with some light showers and more cloud cover. Â The central and southern Cascades should see a mix of sun and clouds. Â Temperatures should be near or slightly cooler than Thursday and winds should increase slightly in the afternoon.Â
The most extensive avalanche concern will be wet snow avalanches predominately on solar slopes Friday. The avalanche danger may be locally lower in the north Cascades due to cooler temperatures and more cloud cover.  Watch for wet surface snow deeper than a few inches, roller balls in surface snow and small natural wet loose releases that usually precede more major wet loose snow avalanches. Avoid terrain traps where a small but powerful wet loose avalanche could have unintended consequences.
Cornices will be listed as a secondary concern due to the recent failures, but they should be less likely to fail Friday. Still, avoid walking onto or below cornices - many have grown large recently. Cornices often break back further from the edge than expected and trigger avalanches on slopes below.
Lingering shallow wind slab above tree line is not expected to be a widespread concern at this time.Â
Snowpack Discussion
Fronts crossed the Northwest Friday and later Saturday. Water and snowfall for these systems at NWAC stations at higher elevations near and west of the crest were in the 0.70 to 2.4 inch and the 5 to 25 inch range respectively. Warm temperatures were seen Sunday and especially Monday.  During this period the recent storm snow and warmer temperatures led to avalanches, some triggered by cornice failures. Crystal mountain pro patrol reported late Monday afternoon a natural point release that became a large wet avalanche that gouged down several feet to older snow layers from past storm cycles near the Bear Pits ski run. Crystal patrol found similar results with explosives Tuesday morning while the upper snowpack was still wet. The DOT crew at Chinook Pass reported widespread ski triggered wet loose avalanches on solar slopes Tuesday.
A weaker front moved through the PNW Tuesday afternoon and night with a colder air mass following Tuesday night. About .50 to.75 inches of rain fell at NWAC stations near and west of the crest with perhaps 2-8 inches of snow above treeline.  Despite cooling Tuesday night, on Wednesday NWAC observer Tom Curtis still found the upper 25 cm of snow on a NE aspect near treeline at White Pass to be wet and available for entrainment (see photo).  With control work Wednesday, the Chinook DOT crew triggered large cornice failures on a east aspect that gouged down a couple of feet.Â
Another night of freezing temperatures Wednesday night allowed a better refreeze of the surface snow with no new avalanches reported on Thursday. Â
Large roller balls after triggered cornice collapse, White Pass, T. Curtis, 4-09-14
Avalanche 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: All elevations.
Likelihood: Possible
Expected Size: 1 - 1
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind lips of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.
Cornices can never be trusted and avoiding them is necessary for safe backcountry travel. Stay well back from ridgeline areas with cornices. They often overhang the ridge edge can be triggered remotely. Avoid areas underneath cornices. Even small Cornice Fall can trigger a larger avalanche and large Cornice Fall can easily crush a human. Periods of significant temperature warm-up are times to be particularly aware.
A corniced ridgeline. A large cornice has formed at the top of the ridge. A smaller cornice has formed to the left of the trees from crossloading.
Cornices are easy to identify and are confined to lee and cross-loaded ridges, sub-ridges, and sharp convexities. They are easiest to trigger during periods of rapid growth (new snow and wind), rapid warming, and during rain-on-snow events. Cornices often catch people by surprise when they break farther back onto flatter areas than expected.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 2