The National Weather Service Forecasts-

TODAY...RAIN SHOWERS DIMINISHING IN THE AFTERNOON. HIGHS AROUND
42. SOUTHEAST WIND 15 MPH SHIFTING TO THE NORTHWEST EARLY IN THE AFTERNOON...THEN BECOMING LIGHT AND VARIABLE LATE IN THE AFTERNOON.

TONIGHT...SCATTERED RAIN SHOWERS...BECOMING MORE NUMEROUS
OVERNIGHT. LOWS AROUND 33. LIGHT WINDS BECOMING SOUTHEAST 10 MPH LATE.

WASHINGTONS BIRTHDAY...NUMEROUS RAIN SHOWERS. HIGHS AROUND 39. SOUTHEAST WIND 10 MPH.

Temperatures continue to remain quite warm. Temperatures have not dipped below freezing at the Mt Roberts Tram Summit in essentially a week.

Yesterday the Tram low was just over freezing, the high was 38f and currently its 33f. Eaglecrest saw freezing for a short while with a low of 31f at mid mountain and a high of 36f. Currently its just over freezing. The bottom is 36f and its 31f at the summit.

These cooler temperatures today and long periods of warm with moderate precip has helped to stabilize the snowpack quite a bit.

For the most part avalanche danger is LOW today. Yet a possibility of Natural Avalanches remains in steeper open faces with few anchors at mid to lower elevations.

Stability is continuing to increase the colder it gets.

Be aware of areas of glide still. You can see these areas opening up and they are very predictable. Do not spend time above or below these areas.

I saw two glide avalanches yesterday. Watch the areas where you spend time to check for glide cracks.

With not much precip in the forecast and cooler temps forecast for tomorrow as we go into evening avalanche danger will continue to fall into tomorrow.

Know the Snow: Glide avalanches Written for Juneau Empire 2012.

By Ron Simenhois

Know the Snow

Sometime late November, I was sitting and talking about the heavy early season snowfall with Brian Davies, Eaglecrest patrol director. At some point Brian said that this could be a big glide avalanche season. Like in many other cases when we have talked about snow and avalanches, Davies? prediction was right.

Currently, more and more signs of gliding activity are clearly visible on the mountains around us. Although not unique to Southeast Alaska, they are relatively uncommon in other snow climates.

Glide avalanches have kept me from a good night?s sleep more than once since I moved to Juneau.

But, I am not alone.

They are known as a nightmare for avalanche professionals worldwide. They are extremely difficult to forecast, they are almost impossible to control with explosives and are often very destructive as they mobilize large volumes of snow. To my knowledge, glide avalanches destroyed at least two chair lifts in Europe this year. One of these avalanches got caught on tape and went viral over the internet (You can see it here: http://www.youtube.com/watch?v=og5h-E-Ntsk&feature=related).

Glide avalanches occur when the entire snowpack glides over the ground. The relatively slow gliding process can take place over a few hours and up to several months. If the gliding snowpack breaks free from its supporting boundaries, an avalanche will transpire. An obvious clue of snow gliding are the cracks in the snowpack that appear on steep slopes this time of year. Excessive snowpack gliding and its associated glide cracks tend to form on specific slopes. These slopes are typically steep and covered with smooth gliding surfaces like rock slab, weeds or bent over alders. Active glide avalanche paths can sometimes produce more than one avalanche in a winter.

Forecasting glide avalanches is still an unanswered challenge for the avalanche community. The difficulty of forecasting glide avalanches is not due to lack of understanding glide processes. Glide processes have been researched over the years and are relatively well understood. The problem lies with the distance of the glide process from the snow surface. The gliding interface is at the base of the snow cover. Thus, gliding rates are hard to gauge and traditional forecasting methods like snowpack and weather observations have proven inaccurate.

Two years ago, I was trying to see if there was any correlation between glide avalanche events, stream flow below the avalanche slope, time of day and weather events like temperatures, snow and rain. I came up empty. I found no obvious direct correlation between glide avalanches and environmental or climates events.

In my personal experience, controlling glide avalanches has been just as challenging as forecasting them. I have had mixed results trying to control these avalanches using explosives. In many cases, I used very different strategies than for other types of avalanches and the gliding seemed to stop. But I could never tell for sure if that was due to the avalanche control or other reasons.

To my knowledge, there is very little knowledge on artificial control methods for glide avalanches. Other folks that deal with glide avalanches also agree that they are extremely hard to trigger with explosives. In fact, the Swiss resorted to excavators and snow cats to trigger or break the gliding snow, rather than using explosives, whenever they can.

When I travel in the mountains, I rely on my knowledge and experience to keep myself safe. However, when the avalanche problem of the day is glide avalanches, my forecasting abilities are admittedly somewhat limited. On these days, I rely on the fact that glide avalanches occur in very specific places. I maintain and update a mental map of where gliding occurs and avoid those areas altogether.

This year is a good year to pay attention and recognize these places where glide cracks and avalanches develop.

LIVE TO RIDE ANOTHER DAY!

Eaglecrest is hosting an Backcountry Safety Awareness and Companion Rescue Course Saturday March 5th from 8:30am-3:30pm.

This course is free and sponsored by the Department of Public Safety.

During this day long course you will learn about avalanche terrain, weather, and stability assessment tests. You will also learn about Avalanche Rescue as well as transceiver, probe and shovel use.

Please share this offering with your friends. Lets all do out part to maintain a safe backcountry community.

For more information or to sign up please email [email protected]