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

Apr 3rd, 2015–Apr 4th, 2015

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

Regions

Mt Hood.

New snow should require careful snow and terrain evaluation at Mt Hood Saturday.

Detailed Forecast

Weak flow and mostly light showers should move out of a low or form over the Northwest in a cool slightly unstable air mass Saturday afternoon. These showers may be more likely during the afternoon hours near the volcanoes such at Mt Hood.

Watch for possible new shallow wind and storm slab from Friday. These layers would be deeper if you find an area that has more snowfall such as on Mt Hood.

It is April and the sun is getting much stronger. So possible loose wet avalanches will remain in the forecast as well. Solar slopes in any area with significant new snow from Friday will be very susceptible on Saturday.

Cornices won't be listed as an avalanche problem but use caution on slopes below cornices and on ridges where it can be hard to know if a cornice is present.

Snowpack Discussion

Active weather and periods of snowfall have been seen since about mid March. Snowfall during this period was limited near and below treeline at Mt Hood but greater above treeline. There have also been periods of consolidation and stabilizing at Mt Hood.

A front moved across the Northwest Tuesday followed by showers and rapid cooling Tuesday night and Wednesday. Storm snow from this system was about 9-15 inches at Mt Hood. The patrol at Meadows on Wednesday reported that the storm snow was surprisingly less reactive than anticipated. The storm snow produced some 6-12 inch loose dry and very soft storm slab avalanches from explosive control with no ski released avalanches.

Cool weather with no rain or snow was seen Thursday and much of Friday. The Meadows patrol reported no avalanches with firm snow or surface snow getting heavy on solar slopes and staying cool on north slopes.

Another front and short wave trough are crossing the Northwest Friday afternoon. This should be accompanied by moderate southwest winds and mostly light to moderate rain or snow in the Cascades. Snow showers should decrease pretty rapidly Friday evening. A couple to a few inches of new snow should be seen at Mt Hood. 

Snowpack problems at Mt Hood should remain in the upper or surface layers. The mid and lower snowpack at Mt Hood consists of layers of stable consolidated rounded grains or melt forms and crusts from multiple warm periods this season. Many areas at low elevations do not have enough snow to cause an avalanche danger.

Problems

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.

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.

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.