Avalanche Forecast

A deep low pressure system should move over about Cape Flattery and across south Vancouver Island Sunday morning and afternoon. This should bring stormy weather and heavy snow to Mt Hood Sunday. This is a little faster than previously expected. A vigorous, strong front should rapidly cross the area and cause rapidly shifting winds Sunday.

The main avalanche problem Sunday should be increasing strong winds and increasing moderate to heavy snow rapidly transporting recent or new snow and building new wind slab on lee slopes. This is very likely to be northwest to southeast slopes. New storm slab should also be likely where there is rapidly accumulating new snowfall.

The pattern makes for a tricky forecast Sunday. Dangerous avalanche conditions are expected to develop Sunday afternoon. Back country travel is not recommended in the near and above treeline by Sunday afternoon at Mt Hood.

Weather and Snowpack

The nonstop active weather pattern continues to push a storm system through the PNW almost every day or two resulting in fluctuating snow levels and periods of very strong winds (100+ mph gusts have been seen at the Mt Hood Meadows Cascade Express station over the last 2 weeks).

A last storm arrived Wednesday bringing heavy snowfall/rain at rising temperatures and very strong S-SW ridge top winds. About 2 inches of water and 8 inches of snow was seen the the NWAC stations at Mt Hood Meadows and Timberline for the 2 days ending Thursday morning with much of the water in liquid form. 

A front on Saturday is causing west-southwest winds and there should be up to a few inches of new snow at Mt Hood by Sunday morning.  

The mid and lower snow pack at Mt Hood should be a stable mix of crusts and layers of moist and rounded snow crystals.

Recent Observations

On Wednesday morning, new extensive wind slabs were forming on lee slopes near and above treeline. Explosive control performed by Mt. Hood Meadows pro-patrol Wednesday produced widespread slab releases on wind loaded N-NE facing terrain with crown depths of 2 feet common. Storm slabs Wednesday morning changed to loose-wet avalanches by midday as temperatures rose and snow changed to rain below treeline. 

On Thursday, NWAC pro-observer Laura Green toured in the Mitchell and Heather drainages and found evidence of rain up to at least 6600 feet. Thin wind pockets were observed on lee slopes above treeline. A supportable rain crust did not make for good skiing, but on the plus side no avalanche problems were noted. Runnels were observed below 6000'.