The National Weather Service Forecasts-

TONIGHT...SNOW SHOWERS. SNOW ACCUMULATION 2 TO 5 INCHES. LOWS
AROUND 25. EAST WIND 10 TO 20 MPH WITH HIGHER GUSTS.

FRIDAY...SNOW SHOWERS. SNOW ACCUMULATION 1 TO 3 INCHES. HIGHS
AROUND 30. SOUTHEAST WIND 10 TO 15 MPH.

FRIDAY NIGHT...NUMEROUS SNOW SHOWERS. SNOW ACCUMULATION 1 TO
2 INCHES. LOWS AROUND 27. SOUTHEAST WIND 10 TO 15 MPH.

We are seeing 25+ knot winds currently out of the East. We have a lot of loose snow on the hill today. This is directly loading the urban starting zones. Winds load slopes faster than new snow can from falling and tends to build weak layers and slabs.

We will also be seeing several inches on new snow overnight adding to the equasion with building stress in the snowpack.

Todays field results showed weak layers in the snowpack that were being skier triggered which shows they are close to natural failure which can lead to avalanches.

Temperatures are expected to remain cool. Winds will be considerable overnight and will continue to load our urban paths.

The lower deep layers in the snowpack have started to settle some and bond yet there are still many weak layers present at different depths.

Should avalanches occur they have the potential to tear down to the deeper weak layers in place.

Avalanche danger is HIGH overnight tonight with the direct windloading on top of the current weak layers.

Tonight is a great time to avoid travel in the urban avalanche zones especially along Thane Road, The Flume and Perseverance Trails.

The Berhands and White path avalanche zones are also extremely loaded with snow right now and this wind event could start dry slab avalanches which travel quite fast and have the ability to cause damage even from the wind blast that procedes them and also travels farther then the avalanche itself. This forecast will be updated before 7am tomorrow.

Potentially destructive natural avalanches likely to come near or reach developed areas.

Natural and human triggered avalanches likely, especially if we see more snow than originally forecast or greater loading winds.

Here is a little info for you from the storm system that built the deeper weak layers currently in place over the last few days.

On Sunday we received approx. 7\" of new snow in our mountain starting zones. This came in fairly dense and is bonding well in most places.

From Monday into Tuesday we received about 20m of precip that left about 28cm (10-11\")of approx 7% snow (light and dry).

From Tuesday evening into Wednesday we received another 26mm of precip that left about 20cm (8\") of approx. 13% new snow (wetter and heavier).

Temperatures rose all day Tuesday by about 7 degrees right to the point of freezing at tram summit elevations and peaked out by about midnight. Wednesday AM until now they have cooled off by 7C degrees and we have seen several inches of new snow on top of the lower weak layers.

So we placed a 10+\" layer of pop cans down (low density), then we covered it up with about an 8\" thick cinder block (higher density). Now we are finishing it off with another several inches of moderate density snow and loading winds.

It is only a matter of time until the pop cans colapse.

Hopefully winds will die off or shift direction and new snow loading will be at a minimum.

Aviod spending time in the urban avalanche zones.

Trigger:

Most avalanches are ?naturally? triggered, meaning that weather (wind, snow, rain or sun) stress the snowpack to its breaking point. Like a tree falling in the woods, for the most part, we only care about the ones that affect people. Luckily, in 92 percent of avalanche accidents, the avalanche is triggered by the victim or someone in the victim?s party. In other words, most avalanche accidents happen by choice, not chance. These are ?human triggered? avalanches. In other words, weather adds stress to the snowpack until it nearly equals the strength of the snowpack. Then, the added weight of a person provides the final thump to initiate a fracture within the buried weak layer. (No, noise does NOT trigger avalanches. It?s a clich? plot device in the movies, but noise is simply not enough force to trigger an avalanche.)

We can also think of snow stability in terms of the size of trigger required to trigger an avalanche. Notice that when natural avalanches are occurring, the stability meter is pegged out at the top of the scale. That?s why the best sign of avalanche danger is another avalanche on a similar slope.

Wind is one of the biggest triggers of natural avalanches and should always be considered.