Avalanche Forecast
Regions: Olympics.
The avalanche danger should increase at Hurricane by Friday afternoon.
Detailed Forecast
West flow and an atmospheric river (aka the Pineapple Express) of warm front moisture will begin moving over the upper ridge and to the Northwest on Friday. Rain or snow should become moderate to heavy mainly in the Olympics and north to central Cascades by Friday afternoon and continue Friday night with rising snow levels.
Loose wet and and wet slab avalanches will be listed as the avalanche problems in all areas west of the crest including the Olympics on Friday. At Hurricane these problems should be limited to slopes holding significant recent snowfall.
Often loose wet avalanches occur just prior to wet slab avalanches. Avoid steep slopes if you are in increasing heavy rain and start to see wet snow deeper than a few inches or increasing natural pinwheels or rollerballs. The avalanche danger should continue to increase Friday night.
There is some uncertainty in this forecast. If the heaviest rain occurs Friday night then the greater avalanche danger may also occur Friday night.
Snowpack Discussion
Snow on the back end of the last storm Sunday and Monday was about 7 inches at Hurricane.
NWAC pro-observer Katy Reid was at Hurricane on Sunday. She mainly reported poor coverage and shallow new snow well bonded to previous melt form snow. She also reported stable melt form layers in the mid and base pack where it existed. Here is her video from Sunday on our YouTube Channel.
A weak dissipating front is moving across the Olympics and Cascades on Thursday. Snow and rain amounts are expected to be light and not have a great effect on snow conditions.
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: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 1
Wet Slabs
Release of a cohesive layer of snow (a slab) that is generally moist or wet when the flow of liquid water weakens the bond between the slab and the surface below (snow or ground). They often occur during prolonged warming events and/or rain-on-snow events. Wet Slab avalanches can be very destructive.
Avoid terrain where and when you suspect Wet Slab avalanche activity. Give yourself a wide safety buffer to handle the uncertainty
A Wet Slab avalanche. In this avalanche, the meltwater pooled above a dusty layer of snow. Note all the smaller wet loose avalanches to either side.
Wet slabs occur when there is liquid water in the snowpack, and can release during the first few days of a warming period. Travel early in the day and avoiding avalanche paths when you see pinwheels, roller balls, loose wet avalanches, and during rain-on-snow events.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1