Avalanche Advisory Archive Pre-2016

Date Issued:2010-12-15
Danger:1
Trend:3
Probability:3
Size:1
Problem:0
Discussion:

The National Weather Service Forecasts-

TODAY...MOSTLY CLOUDY. CHANCE OF SNOW IN THE AFTERNOON. LOCALLY BREEZY. HIGHS 24 TO 30. EAST WIND 15 TO 25 MPH. HIGHER GUSTS OUT OF INTERIOR PASSES.

TONIGHT...MOSTLY CLOUDY. SLIGHT CHANCE OF SNOW IN THE EVENING. LOWS 13 TO 19. EAST WIND 15 TO 20 MPH.

THURSDAY...MOSTLY CLOUDY. LOCALLY BREEZY. SLIGHT CHANCE OF SNOW IN THE MORNING. HIGHS AROUND 25. SOUTHEAST WIND 10 TO 20 MPH. HIGHER WINDS AND GUSTS OUT OF INTERIOR PASSES.

THURSDAY NIGHT...MOSTLY CLOUDY. LOCALLY BREEZY. LOWS 11 TO 19. SOUTHEAST WIND 10 TO 20 MPH. HIGHER WINDS AND GUSTS OUT OF
INTERIOR PASSES.

With the warm weather from 10 days ago, the rain and heavy dense snow, the lower snowpack has settled and bonded quite a bit.

There are still multiple weak layers lower in the snowpack but the heavy dense snow above them appears to be supportive at this time. Be cautious as new loads are placed on these already weak layers by new snow or even by additional wind loading.

We had several inches of new snow deposited Saturday and Monday. This has placed some additional weakness in the snowpack in places with wind deposits.

Look to see continued areas of wind loading as the snow in place is affected by winds of 10+ MPH throughout most of the next few days.

With very little snow on Mt Juneau in the urban starting zones avalanche danger is LOW at this time. Yet some of the gullies are starting to see fair snow accumulation due to crossloading from the winds.

Please remember this is not a backcountry forecast.

Please be aware that fieldwork continues to show multiple weak layers in the snowpack.

Backcountry danger levels could be considerably higher.

Tip:

Winds change snow stability.

Windward slopes often become packed. This can lead to hard slab avalanches. Yet after long periods of high winds the windward slopes can often become scoured of snow leaving them safe for travel.

Lee slopes often see snow deposited from storm winds. This is a common cause of slab avalanches.

If you are seeing winds of 10+ MPH in the forecast you should be thinking of their effects on the slope in relation to aspect and elevation.

Remember during periods of snow fall. Rising temperatures place heavy dense snow above the looser lighter snow that fell at cooler temperatures.

Common signs of instability include rising temperatures throughout a storm cycle.