Avalanche Forecast
Regions: Olympics.
Loose wet or possible wet slab avalanches on all aspects to near treeline will again be the primary concern Thursday. Also give recently formed cornices a wide berth and avoid travel under slopes with large overhanging cornices.
Detailed Forecast
Mostly cloudy conditions and light showers Wednesday night may prevent a healthy refreeze on wet surface snow. Â Snow levels will be slightly cooler Thursday but wet-loose avalanches will still be the primary concern especially during any potential sunny periods in the late morning through mid-day.Â
Watch for wet surface snow conditions and given the deep recent storm snow, expect any wet-loose avalanches that start small to possibly entrain large amounts of snow.  Avoid terrain traps and steep slopes and watch for signs of natural wet loose activity.  Â
Cornices have grown large over the last 2 weeks. A cornice failure could provide a large enough load to trigger a destructive avalanche. With the warming Tuesday...expect cornices to become more sensitive and likely to fail. Â
Continue your careful snow pack evaluation and cautious terrain selections during the work week.
Snowpack Discussion
Recent Northwest Weather
An extended mild and dry period occurred the latter half of January generally forming a crust in all areas. Very cold weather followed in early February which produced light low density snowfall, near surface faceting, and faceting near and just above the crust.
Weaker frontal systems last weekend followed the frequent strong storms over the past 2 weeks.  We have finally ended the extended storm cycle as of Monday night, capping off impressive amounts of some 6-7 feet of new snow with a rain event that reached to near 7000 feet in the Hurricane Ridge area and likely other Olympic areas.Â
Tuesday and Wednesday has seen well above freezing temperatures with periods of sunshine.  Hurricane Ridge high temperatures reached into the upper 40s both days.
Observations for Hurricane Ridge area
Recent deep snow conditions took a dramatic turn for the worse Monday in the near and below tree line zones as rain returned and fell through Monday night.  The generally light to moderate rain that fell through late Monday night has quickly changed the recent low density dry snow to wet snow conditions.  An NPS ranger at Hurricane Ridge Tuesday morning reported evidence of recent widespread wet snow avalanches running on most steeper slopes and a variety of aspects.  This situation likely repeated itself on Wednesday especially during sun breaks.Â
Several avalanche cycles have occurred over the last 2 weeks. The last natural cycle likely occurred during the middle of last week when the road to Hurricane Ridge was closed. NPS employees found avalanche debris up to 8' deep just off the Hurricane Ridge road at 3600 ft while plowing Thursday. The start zone was likely in the near-treeline zone on a S-SE aspect.Â
The late January crust layer and associated weak layers of early February are now deeply buried by all the new storm snow, but still producing areas of collapsing and large whumpfing as reported in a NE meadow below treeline by a frequent TAY-er in the Hurricane Ridge area this weekend. The same skier had pictures of some very large cornice collapses.
On Sunday Feb 23, NWAC observer Katy Reid found relatively stable profile of right side up storm snow, meaning lower density surface snow accumulating on denser older snow layers with little avalanche activity through the day.  However some warming in the afternoon did cause some surface cohesion producing some shooting cracks from skies as shallow soft slabs formed.  On Friday stubborn but still possible to ski trigger wind slab were found on northerly aspects above treeline. She also observed quickly releasing wet loose avalanches on below treeline on solar aspects reacting to the strengthening February sunshine. With the addition of Monday's rain and Tuesday/Wednesday's sunny periods and warming these loose-wet slides should grow in number. Â
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Shallow soft slab cracking due to afternoon warming.  D2 loose-dry slide.  Sunday 2/23 Maggies, Hurricane Ridge by Katy Reid.
The mid and base pack at Hurricane should still consist of mostly stable crusts and melt form layers from periods of warm weather earlier this winter.
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.
Elevations: All elevations.
Likelihood: Likely
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, North West.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2