Avalanche Forecast

Archived

Feb 13th, 2017–Feb 14th, 2017

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 possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Regions

Mt Hood.

Tuesday should be a mostly safe avalanche day in the Olympics and Cascades. Watch for signs of loose wet snow steep sun exposed slopes. Use caution travelling on steep slopes with a slick surface crust.

Detailed Forecast

Tuesday morning should start out mostly sunny but increasing high clouds will be seen at Mt Hood Tuesday afternoon. Alpine winds will increase with high freezing levels and mild temperatures. Significant rain or snow should hold off until Tuesday night and Wednesday.

Some initial sunshine and another day of mild temperatures Tuesday should make loose wet avalanches possible on steep slopes facing the sun. Be cautious on sun exposed slopes if the wet surface snow becomes deeper than a few inches.

Older wind slabs should have mostly settled and stabilized the past couple days. Significant new wind slab is not expected Tuesday as southeast to southwest winds won't transport sun affected snow. But continue to watch for signs of wind deposited snow on north facing terrain features.

Some slopes exposed to recent winds or where less new snow was received after rain changed to snow may have an exposed very slick crust. Be cautious of uncontrolled falls and avoid traveling on steep slopes with slick crust in terrain where an uncontrolled fall could have serious consequences.

Snowpack Discussion

Weather and Snowpack

A strong storm cycle Friday, 2/3 through Monday 2/6 deposited about 3-4 feet of snow on Mt Hood.

Strong SSW flow carried a frontal system with deep moisture across the Northwest on Wednesday 2/8 and Thursday 2/9. About 2 inches of water fell mainly as rain on Mt. Hood from by Thursday afternoon with significant snowpack settlement.

Friday was windy with a slow cooling trend with about 6-8 inches of new snow by Saturday morning.

High pressure Saturday to Monday brought increasing sunshine and warming temperatures. Temperatures reached the 40's and 50's in many areas of the Olympics and Cascades on Monday. This has brought snowpack settlement, some small loose wet avalanche activity and a decreasing avalanche danger.

Recent Observations

On Thursday the Meadows pro-patrol reported saturated snow down 25 cm but no avalanche activity in the ski area. The upper mountain was not observed due to strong winds and limited visibility.

By Friday morning Meadows pro-patrol reported widespread loose wet and small wet slab natural activity had occurred Thursday near and above treeline. One very large wet slab occurred in the God’s Wall path up to size D3, likely releasing sometime Thursday. Below treeline a saturated snowpack was still re-freezing and became less supportable at lower elevations.

By Sunday a very strong and supportable rain crust lies beneath the settled 6-8 inches of surface snow.

The Meadows pro-patrol reported only some roller balls on solar slopes and no other signs of instability on Monday.

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.