Current Advisory as of Saturday, February 6, 2010

Expires 7:00am on Wednesday, February 10, 2010
Issued by Tom Mattice

Today's Discussion

The National Weather Service Forecasts- TODAY...RAIN SHOWERS IN THE MORNING...THEN BECOMING MOSTLY CLOUDY WITH A CHANCE OF RAIN AND SNOW SHOWERS IN THE AFTERNOON. SNOW LEVEL 1200 FEET IN THE MORNING LOWERING TO AROUND 400 FEET IN THE AFTERNOON. TEMPERATURES SLOWLY FALLING TO AROUND 35. SOUTH WIND 10 TO 15 MPH IN THE MORNING BECOMING LIGHT AND VARIABLE.

TONIGHT...MOSTLY CLOUDY WITH A 30 PERCENT CHANCE OF RAIN AND
SNOW SHOWERS. LOWS AROUND 33. LIGHT WINDS.

TUESDAY...MOSTLY CLOUDY. CHANCE OF SNOW AND RAIN IN THE MORNING THEN A CHANCE OF RAIN IN THE AFTERNOON. HIGHS AROUND
37. EAST WIND 15 MPH. CHANCE OF PRECIPITATION 30 PERCENT.

With very little new snow in the last week things are farily stable at this time.

We have seen more above freezing temperature on Mt Roberts and Mt Juneau than below freezing temperatures in the last week. This was slowly weekening the snowpack. Today we are once again seeing above freezing temperatures on most of the mountain. This should start to cool off today and tonight.

As long as rain or snow comes in slowly or not at all danger levels should remain moderate.

Currently at lower elevations the bottom 2/3 of the snowpack is moist, warm, and rotten. There is some bonding and bridging above this layer. Yet the weakness is quite present and needs quite a bit of time at below freezing temperatures if it is to resolidify.

Do to the continued rains and above freezing temperatures we are starting to be concerned with free moinsture in the snowpack. This moisture continues to eat at the bonds in the snowpack. Areas on steep open slopes are becoming more suspect. Thin snow cover on rocks in places may start to clean off as well. Also watch slopes with glide cracks as the prolonged temps can cause rapid glide activity which will add increased stress to the slabs in place. Backcountry danger may be considerable in places.

As the cooling comes in things will start to stabilize slowly.

Today's Avalanche Tip

Below freezing temperatures are like the glue that helps to hold the snowpack together. During periods of above freezing temperature the bonds that have formed between the crystals erode and disappear. The longer the period of warm temperature the more the snowpack tends to weaken.

Rain has this same effect by rapidly warming the snowpack as well as eating away at the corners of the flakes and the bonds holding them together.

Once the snowpack warms it takes a tremendous amount of time and energy to bring it back down in temperature.

The most recent snow came in as rain and slowly turned into snow. This warm snow sticks well to the old snow surface. Today we will start to again see warmer temperatures. Look to see avalanche danger levels rise as the temps start to warm back up during periods of continued rain.

Hopefully as we move towards tomorrow and cooling things will start to stabilize more..