Avalanche Forecast
Regions: Cascades - East.
Fresh wind and storm slabs may be poorly bonded to the old snow surface or crust layer. Caution in steep open terrain near and above treeline. Watch for wet snow conditions at lower elevations.
Detailed Forecast
A continued cooling trend is expected Friday with diminishing winds and a few light snow showers possible. This should allow recent wind and storm slabs to slowly settle and improve in higher elevation terrain. The cooling should allow for wet snow at lower elevations to begin re-freezing and strengthening.Â
Watch for any wet snow conditions at lower elevations, especially on steep unsupported terrain features.
Avoid steep wind loaded terrain Friday, mainly below ridges, near and above treeline.Â
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Snowpack Discussion
Weather and Snowpack
The 2/8 - 2/10 storm cycle deposited 2-3 feet of snow in the Washington Pass area. In the central-east and southeast zones a rain crust formed with shallow amounts of new snow following at the tail end of the cycle. This storm cycle was a great test for any Persistent Weak Layers buried deeper in the snowpack. There was no evidence of any deeper releases and as a result, we have removed Persistent Slab from the problem list.
High pressure Saturday to Tuesday brought increasing sunshine and warming temperatures. Temperatures reached the 30's and 40's in many areas along the Cascade east slopes. This caused snowpack settlement, some small loose wet avalanche activity and a decreasing avalanche danger.
Another atmospheric river impacted the PNW beginning on Wednesday.  Light to moderate snow with warmer temperatures and some high snow levels occurred along the east slopes of the Cascades with localized freezing rain along the lower east slopes. Above freezing temperatures occurred during precipitation with light rain likely in the southeast zone up to 7000 feet, 5000-6000 feet in the central-east and reports from the north-east zone of a thin freezing-rain crust to near treeline elevations at least.Â
Recent Observations
North
A report via the NWAC Observations page indicates a shallow climax slab avalanche on a north slope on Mt Patterson near Winthrop on Sunday. There is likely to be shallow faceted snow in this low elevation area.
NWAC observer Jeff Ward was out Thursday, 2/16 and reported the recent about 10 inches of  moist storm snow was being transported and building wind slabs through the day. There was evidence of a few natural wind slab releases and a natural storm slab was noted releasing sometime Thursday. A thin freezing rain crust formed mid-storm cycle and was yet to form a good bond as of Thursday. Â
Central
NWAC's Tom Curtis travelled in the Icicle Creek area near Cashmere Mountain Saturday 2/11. Tom did not get far as there was only a dusting of recent snow over a slick, firm crust. The greatest danger in this area was from uncontrolled falls on the slick crust as opposed to avalanches.Â
Another report via the NWAC Observations page for Dirty Face Peak for Sunday indicates that wind slab was unreactive there on Sunday.
Reports from the Mission Ridge pro-patrol mostly indicate a breakable surface crust from late last week and poor ski conditions Sunday and Monday.
Thursday afternoon 2/16, warm temperatures had reached the lower east slopes and numerous wet snow avalanches had released, including in Tumwater Canyon.
South
No recent observations.Â
Avalanche Problems
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.
Elevations: Below Treeline.
Likelihood: Possible
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: Below Treeline.
Likelihood: Possible
Expected Size: 1 - 1
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.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1 - 1