Avalanche Forecast
Regions: Olympics.
Increasing winds on Wednesday will move new and older snow to form shallow wind slabs on Wednesday. Mitigate hazard by approaching lee slopes with caution above treeline.
Detailed Forecast
Light rain and snow Wednesday morning is expected to become light to moderate rain during the afternoon hours at Hurricane Ridge. Moderate ridge-top winds will increase and may become strong during the afternoon hours.
Watch for the development of shallow wind slabs during the morning hours before a changeover to rain. Monitor new snow and wind transport diligently throughout the day and avoid wind-loaded slopes where wind slabs may be possible to trigger above treeline and are most likely on W-N-E aspects.
Despite the recent snow, early season hazards still exist. Many creek beds have still not filled in for the winter.
Snowpack Discussion
Several inches of dry snow fell was available for transport by light to moderate winds on Tuesday. This snow sits on a combination of rain crust (formed Monday night) and adding to solar crusts formed in melt-freeze conditions during the high pressure ridge Saturday through Monday.
A foot of snow from last Thursday has now settled and is bonding to the previous recent rain crust. Below this rain crust, no notable layers of concern have been identified within the snowpack.
The height of snow across the terrain is quite variable with little snow in many areas below treeline. Numerous obstacles still exist at all elevations.
Observations
NPS rangers reported a skier triggered avalanche from the Hurricane Ridge area Saturday morning. The avalanche occurred as the skier was traversing across a steep convex rollover locally known as Avalanche Run near Poma Bowl (SW aspect around 5300 feet). The avalanche was estimated to be 12 inches deep, about 100 feet wide, and ran down slope for 300-400 feet. The skier was caught and carried but did not sustain any injuries.
Skier triggered wet snow avalanche 1/13, releasing on traverse (upper right). photo: NPS ranger
A separate natural, loose-wet avalanche occurred on Saturday in a known avalanche path named 20th of June. The avalanche occurred around 10am and ran for 300-400’.
Rangers also noted several glide cracks on steep smooth rock slabs.
Avalanche Problems
Wind Slabs
Release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Wind Slabs form in specific areas, and are confined to lee and cross-loaded terrain features. They can be avoided by sticking to sheltered or wind-scoured areas..
Wind Slab avalanche. Winds blew from left to right. The area above the ridge has been scoured, and the snow drifted into a wind slab on the slope below.
Wind slabs can take up to a week to stabilize. They are confined to lee and cross-loaded terrain features and can be avoided by sticking to sheltered or wind scoured areas.
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 1