Avalanche Forecast

Archived

Apr 23rd, 2014–Apr 24th, 2014

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Alpine

Below Threshold.

Treeline

Below Threshold.

Below Treeline

Below Threshold.

Regions

Stevens Pass.

Heightened avalanche conditions are expected in this area on Wednesday mainly near and west of the crest. Evaluation snow and terrain carefully and identify snow conditions and terrain features of concern.

Detailed Forecast

Showers should decrease and become light in most of the Washington Cascades on Wednesday. But snow showers are going to be slower to let up at Mt Rainier and are not expected to let up much at all and remain moderate to heavy on Wednesday at Mt Hood.

New snow will be very susceptible to strong spring solar effects and strong daytime warming!

Especially where snowfall is heaviest in the south Cascades and Mt Hood. Avalanche concerns in this brief statement will be listed as very likely at Mt Hood, likely for the Snoqualmie to Mt Rainier area, and possible for the Baker to Stevens area.

Snowpack Discussion

It might be late April but Mother Nature isn't watching the calendar and more weather systems have been moving across the Northwest so far this week.

New snowfall for the 24 hours ending Wednesday morning varies quite a bit from north to south with about 2-3 inches from Baker to Stevens, about 5 inches Snoqualmie to Crystal and about 12 inches Paradise to Hood mainly in the ATL and NTL zones. A little less is likely at Hurricane and along the Cascade east slopes.

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.

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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

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.