The National Weather Service Forecasts-

TODAY...SNOW AND RAIN IN THE MORNING...THEN RAIN IN THE
AFTERNOON. SNOW ACCUMULATION UP TO 1 INCH. SNOW LEVEL 200 FEET
RISING TO 1500 FEET IN THE AFTERNOON. HIGHS AROUND 37. SOUTHEAST WIND 10 MPH.

TONIGHT...RAIN. LOWS AROUND 36. SOUTHEAST WIND 10 MPH.

NEW YEARS DAY...RAIN LIKELY. HIGHS AROUND 39. LIGHT WINDS.

SATURDAY NIGHT...CLOUDY. CHANCE OF RAIN. LOWS AROUND 34. LIGHT
WINDS.

We received quite a bit of new snow in the last few days. Over a foot on several weather stations around town.

We received .8\" of moisture in the last 24 hours in the urban path areas. This is a orange flag indicator as to the loading rate.

The winds have averaged above 10 mph for over 36 hours on Mt Roberts, with long periods in the 20's and into the 30's. Winds have averaged above 25mph during that same time on Douglas Island with gusts well into the 40's. These are red flag indicators of windloading.

Temperatures have risen an average of 8 degrees during the last 36 hours. Accompanied by the heavy snow and winds this is another red flag indicator of direct action avalanche conditions.

Yesterday some slabs were pulling loose and pockets of instability were easily skier triggered. Shooting cracks were evident in places and the snowpack sounded hollow walking through deeper wind drifts. This is #4 of the 5 red flag indicators for direct action avalanches.

The last indicator for direct action avalanches is simply viewing recent avalanches.

As daylight comes on today it will be interesting to see if we see much in the way of natural avalanching currently.

Todays moisture models were lowered. Last night we did not receive nearly as much moisture as predicted. So although we are seeing 4 of the 5 red flag indicators it may take a little longer to go into a natural cycle.

Todays temperatures are predicted to rise to 37 at sea level with as much as .31 inches of moisture throughout the day. Tomorrow's temperatures are expected to rise to 39 with as much as .81 inches of moisture. We should start to see natural avalanche activity already but in the next 2 days the slopes will have a great deal of additional stress placed on them.

Although much of the snow this season has been light and simply blown off the faces of Mt Roberts and Mt Juneau, this is quite deceiving. There are several natural gullies and ridges on the slopes. These features gather snow with up channel winds in the form of cross loading. So in most areas there is only 1 to 2 feet of snow, yet in these loaded areas the possibility exists for snow depths in excess of 10'.

As the rain line rises through the elevations watch to see additional activity as the rain places stress on an already weak snowpack.

If the rain line stays high and heavy rains persist for longer periods of time the possibility exists for the water running down the hill to simply undercut the snow and release if from steep rocky faces and areas with fewer anchors.

DOT will be shooting Thane Road this morning to see if they can pull down some of the deeper weak layers of instability we have seen through the early part of the season. The goal is to releive the stress in the snowpack during a time when the road is closed and access in controlled. We may or may not see large slides. But the reality is simply shooting the slope faces will impact the weak layers and help to build long term stability in the snowpack for later in the season. Thats not to say it still could not avalanche. But the goal is to reduce the depth and size of that avalanche should it occur during non controlled times.

Avalanches today are not expected to he huge. Yet in longer steeper slopes quite a bit of snow could move.

Extreme caution is recommended anyplace in the backcountry over the next 48 hours.

AVALANCHE DANGER IS HIGH AT THIS TIME

Storm trend:

If it?s snowed, when you?re ready to start looking at current temperatures, determine if they warmed or cooled during the snowfall event. Rising temperatures during a snowfall destabilize the storm snow layer (an upside-down situation) whereas falling temperatures stabilize it (a right-side up situation).

Temperature trend:

As temperatures increase, the snowpack undergoes settlement, deforming and becoming denser. Settlement on an incline results in creep, a slow downhill motion.

?If air temperatures increase rapidly (more than 15?F or 8?C) in less than 12 hours, the rate of creep increases, which can lead to avalanching. This is most critical when temperatures are near or above freezing because the rate of creep increases exponentially with rising temperature.

?If temperatures increase slowly over several days, settlement rates are slower. If air temperatures never rise above freezing for very long, the snowpack deforms slowly and creep rates are slower.

?As temperatures decrease, settlement and creep rates also decrease.

?Prolonged periods of cold temperatures promote the metamorphic processes that form weak layers.

?Warm days and cold nights strengthen the pack, especially overnight and during early morning hours.

?Several days of warmer temperatures followed by colder temperatures also strengthen the pack.

Key points:

?Rapid rises in temperature can destabilize a pack, while slow rises stabilize it (especially if a cooling trend follows)

?Long periods of cold temperatures build weaker snow, which isn?t a problem until the next significant snowfall (which we are now receiving)