27 Feb 2012

New snow is always a nice thing!! But can also be a bad thing. Check out the story below from yesterday.
At 2280 meters the temperature was - 15.5 at 06:00 hrs. Winds were 10-15 KPH from the SSE. At 1550 meters the temperature was - 15, 75 % relative humidity, and the barometer is steady. No new snow overnight. In the valley it is - 13.

For the updated Avalanche Advisory  click here: Avalanche Advisory

It seems that most of the activity yesterday was down around 50 cm on preserved stellars.

Another avalanche fatality on February 25, 2012 bringing the total to 21 fatalities for the 2011-2012 season in the U.S.


An avalanche near Marias Pass, Mont., killed one man and injured another on Saturday.
The men were riding snow bikes in a drainage area off Skyland Road when the avalanche was triggered.
Rescue teams from the Flathead County Sheriff's Office, the Glacier County Sheriff's Office, Glacier County Search and Rescue and North Valley Search and Rescue combined their efforts in search of the victim. The body was recovered about 3:45 p.m. MST (5:45 p.m. EST).
Injuries to the second man were minor.
The death on Saturday marks the third by avalanche this month in northwestern Montana. There have been seven avalanche fatalities in Montana this winter.
"The foothills to the west of the avalanche site recorded up to 6 inches of snow on Saturday evening," said AccuWeather.com Senior Meteorologist Kristina Pydynowski.
Fresh snow on top of existing snow increases the risk of avalanches.


Hi Wayne, 

On our way back from Decker saw a group(5??) hiking across the top of Disease Ridge.
As we got around the corner and were about to drop in to lower Body Bag we looked back to see 3 of the group sideslipping/billygoating through the rocks.
It's a poor zoomed in photo but you can get an idea.
30m above the bottom of the slide is the guy who got dragged through the rocks above him after his friend cut off a slab from the top unsupported section. This ran, caught him while he was in the middle section, and took him through.
He has another 'friend' in the middle section who didn't get taken down.
We waited till his friend made it down to him, they appeared alright. 
Other than that all we could make out was that they had no packs.
Couple other observations from today.
Looked like mostly natural activity from the Friday storm. 
Size 1.5-2 in the area of Don't Swill( the entrance and also left of the wind lip across the traverse to Husume) under last nights snow.
Similar size on Decker N Face,Pattison NW Face size 2. Both visible under last nights snow.
9th hole size 2 also under last nights snow. Ski cut only produced surface sluff.  Fairly firm in the top 1/3.

Jamie May

Thanks Jamie for the information!!!



Some information on another slide in The US. Click here: February 22 Nd Avalanche

For some information on triggers read this:

Triggers


Avalanches are always caused by an external stress on the snow pack; they are not random or spontaneous events. Natural triggers of avalanches include additional precipitation, radiative and convective heating, rock fall, ice fall, and other sudden impacts; however, even a snow pack held at a constant temperature, pressure, and humidity will evolve over time and develop stresses, often from the downslope creep of the snow pack. Human triggers of avalanches include skiers, snowmobiles, and controlled explosive work. The triggering stress load can be either localized to the failure point, or remote. Localized triggers of avalanches are typified by point releases from solar heated rocks. Remotely triggered avalanches occur when a tensile stress wave is transmitted through the slab to the start zone, once the stress wave reaches the start zone a fracture initiates and propagates the failure. Of exceptional note is that avalanches can not only entrain additional snow within the failing slab, but can also, given the sufficient accumulation of overburden due to a smaller avalanche, step down and trigger deeper slab instabilities that would be more resilient against smaller stresses. The triggering of avalanches is an example of critical phenomenon.