Avalanche Forecast
Regions: Olympics.
Watch for generally shallow new wind slab on lee aspects above treeline. Fast moving loose dry avalanches are possible on steep slopes in non-wind affected terrain.
Detailed Forecast
A weak low pressure system moving south along the Washington Coast on Monday should produce light snow showers, mainly in the afternoon for the Olympics. Â
Watch for generally shallow new wind slab formed Saturday afternoon through early Sunday morning on lee aspects. Fresh wind slab may be found above treeline. Be aware that lower density snowfall received Sunday may obscure recently wind loaded slopes. Â
Watch for loose dry avalanches on steeper slopes in non-wind affected terrain. Be especially wary of fast running loose dry avalanches near terrain traps.Â
Give cornices a wide berth when traveling along ridgelines and avoid lingering on slopes below cornices as they may fail at any time.
Snowpack Discussion
Weather and Snowpack
The most recent atmospheric river arrived on Valentines Day 2/14 and formed the uppermost significant rain crust in our snowpack.Â
A pair of storms deposited about a foot of snow in most areas by Monday 2/20. This was combined with periods of moderate to strong W-SW winds, forming wind slabs at the time. A slightly unstable weather pattern last week caused a mix of sun and light snow showers with sun crusts forming on solar aspects.
Saturday and Sunday were mostly cloudy with periods of light snow showers. NPS Rangers reported that 4.5 inches of snow had accumulated over the weekend. The most recent rain crust was supportable in many areas and aspects around Hurricane Ridge.Â
Recent Observations
No observations have been received from the Olympics in the past few days.
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: Possible
Expected Size: 1 - 1
Loose Dry
Release of dry unconsolidated snow. These avalanches typically occur within layers of soft snow near the surface of the snowpack. Loose Dry avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs. Loose Dry avalanches can trigger slab avalanches that break into deeper snow layers.
Loose Dry avalanches are usually relatively harmless to people. They can be hazardous if you are caught and carried into or over a terrain trap (e.g. gully, rocks, dense timber, cliff, crevasse) or down a long slope. Avoid traveling in or above terrain traps when Loose Dry avalanches are likely.
Loose Dry avalanche with the characteristic point initiation and fan shape.
Loose dry avalanches exist throughout the terrain, release at or below the trigger point, and can run in densely-treed areas. Avoid very steep slopes and terrain traps such as cliffs, gullies, or tree wells.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 1