Avalanche Forecast
Regions: Olympics.
The continued warm wet weather Monday will maintain wet snow conditions near and below treeline. New wind slabs and cornices should maintain dangerous avalanche conditions above treeline Monday.
Detailed Forecast
Moderate to occasional heavy rain and snow is expected with high freezing levels, between 6-7000 feet in the Olympics Monday. Winds should be very strong Monday.
Many steep slopes may have released naturally by Monday, locally lowering the danger on those slopes, however on slopes that have not released due to warming and additional load, natural or triggered avalanches should be possible Monday.  Â
Wind slabs should build on lee slopes below ridges at the higher elevations, above treeline.
Watch for fresh cornices along ridges and stay well clear.
Snowpack Discussion
Weather and Snowpack
A large upper ridge over the West Coast  led to the warmest weather of the winter last Sunday through Wednesday. During this stretch, temperatures were well above freezing.  Cooling Friday and light snowfall late Friday through Saturday deposited about 8 inches of storm snow. Warming Sunday turned snowfall to rain once more at Hurricane Ridge with temperatures rising into the upper 30's and climbing Sunday afternoon.
The recent storm snow has consolidated and become wet snow by Sunday. The latest storm snow overlies the melt-freeze crust formed Friday afternoon after the recent warm weather. The underlying snow is well settled and homogenous.
Professional NWAC observer, Matt Schonwald was at Hurricane Ridge on Friday. Recent warmth and persistent winds have generally created a dense and homogeneous snowpack without any layers of concern. In the Hurricane Ridge area the snowdepth falls off rapidly below 4400 feet. Bare patches or thin snow cover is widespread along ridgelines and south through west aspects. Matt and an NPS ranger did observe 2 glide avalanches that likely occurred Thursday night. The larger one, size D2, released in the June 20th path down to a gravel bed. However, except in isolated terrain features, glide avalanches should not be a widespread concern in the Hurricane Ridge area.Â
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: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1
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.
Elevations: Treeline, Below Treeline.
Likelihood: Possible
Expected Size: 1 - 1