Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Jan 19th, 2015–Jan 20th, 2015

Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.

Regions

.

Watch for locally sensitive wind slabs on lee slopes near and above treeline and sun affects on steeper solar slopes Tuesday afternoon.  

Detailed Forecast

Tuesday should be partly to mostly sunny with a gradual warming trend. Recent storm snow should continue to settle, but sunshine and increasing temperatures in the afternoon may activate loose wet avalanches predominately on steeper southerly slopes. Especially watch near and above treeline, where more snow is available for entrainment and could funnel you into a terrain trap.  

Also, there may be pockets of sensitive wind slab mainly on N-E aspects near and above treeline.  

 

Snowpack Discussion

Strong southwest flow carried a wet front across the Cascades Saturday night. This front tapped subtropical moisture which pushed snow levels high and resulted in 2-3 inches of rain for most NWAC sites west of the crest Saturday night. The exception was in the passes where Snoqualmie saw significant freezing rain and Stevens Pass stayed mostly snow through early Sun AM.  Stevens saw the most skier and natural activity Sat night and Sun AM. Winds switched to westerly in the passes Sunday and a gradual cooling trend took place. Another half inch to 2 inches of water for the west slopes fell through Monday morning with snow levels hovering around 3000-3500 ft.  

The new snow on the backside of this storm Sun-Mon generally bonded well to the wet grains or in the Snoqualmie area, a freezing rain crust. No significant avalanche activity was reported by professional patrollers in the Baker or Alpental areas and while pro-observer Jeff H. near Church Mt found wind transport on north aspects near/above treeline, he did not find the new snow reactive. 

Again, the most active area on Monday was Stevens Pass. Pro-patrol at Stevens triggered 15-20" soft wind slabs on N-NE aspects of Cowboy Ridge, releasing down to the wet layer from early Sun morning with ski cuts and explosives. Observer Dallas G. in the Skyline/Moonlight Bowl area Monday found less reactive storm layers in areas with less wind transport. The Stevens Pass avalanche danger rating will be higher and broken out from the other west slope zones. 

Check out Monday's new videos from Dallas and Jeff H. on our YouTube Channel. 

Below the most recent storm snow, the rest of the snowpack should consist of melt-freeze grains and crusts from warm stretches this winter.  

Problems

Loose Wet

Loose Wet avalanches are the 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. 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.

Wind Slabs

Wind Slab avalanches are the 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.