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Thread: Tamarack, ID OB avi
01-20-2006, 10:53 AM #1
Tamarack, ID OB avi
Looks to be skier triggered.
Update issued 1/19/2006
Tamarack Ski Resort reported a skier triggered avalanche north of their resort boundary on Wed 1/18/2006. The avalanche occurred on a south facing slope with a slope angle of of 34 degrees. The bed surface was suspected to be a rain crust which occurred late last week prior to Tuesday's storm cycle which deposited up to two feet of snow. There was no detailed inspection of the avalanche path and the information on this accident is based on ocular estimates. The avalanche was estimated to be 500 feet wide and 600 feet long with a 3 to 5 foot crown. The avalanche was large enough to bend over and snap trees. The skier went for a big ride but managed to come to rest on top of the debris pile basically unhurt but ski-less. The Friends of the Payette Avalanche Center are inspecting the avalanche scene today. Their observation will be posted on their web site at www.payette-avalanche.org
Tamarack ski patrol used explosives for avalanche control work inside the ski area yesterday on 1/18/06. The use of explosives produced large avalanches which propagated over big distances. Natural avalanches were also observed from the ski area on the east side of Council Mountain.
January 18, 2006
This is Jim Fitzgerald from the Payette National Forest Avalanche Center with the avalanche advisory for Wednesday January 18th, and an outlook for Thursday and Friday. This advisory is brought to you with the help of Idaho Department of Parks and Recreation.
The avalanche danger today is estimated to be High. High danger means that natural and human caused avalanches are likely. Unstable slabs exist on a variety of aspects and slope angles. Travel in avalanche terrain is not recommended. This danger rating expires at midnight on Wednesday, January 18th.
A cold front pushed it's way through our reporting area on Saturday night giving the mountains around 6 inches of snow, much colder temperatures, and a shift in the wind direction. The wind changed from a southerly direction to a northerly one and wind speeds reduced from last week. Low temperatures fell to the teens in the valley and single digits in the mountains. This turn about in weather helped to solidify the snow pack. Sunday through Monday afternoon skies partially cleared as we got a reprieve from all of last week's precipitation.
The lull in precipitation did not last for long as Tuesday morning we woke up to another 5 inches of snow and a heavy snow warning for the mountains until early Wednesday morning. Winds shifted around coming out of the south east during the early part of the storm cycle, then out of the south west later in the afternoon, yesterday. Wind speeds were sufficient to transport snow - with northerly aspects getting the brunt of the wind transported snow. Temperatures rose yesterday, during the storm, creating an inverted snow pack. Easy failures were initiated within the new snow as the rising temperatures created a denser layer over the colder, weaker snow layer that fell during the early part of the storm cycle. As the winds worked their way around from east to west we saw new soft slabs form on east, south, and west aspects. These slabs failed easily under the weight of a ski. Our mountains have received over two feet of snow in the last 48 hours. The Secesh snotel site is reporting an impressive 4.5 inches of snow water equivalant (swe) since January 15th. The bottom line is that we have had a tremendous amount of load - put on a weak layer - in a short amount of time.
Temperatures have started to fall as a cold front enters our reporting area bringing the possibility of numerous snow showers for the remainder of the day. Winds have also decreased as the large winter storm has moved east of us. Currently temperatures in McCall are 32 degrees with light snow falling. Upper elevations are at 22 degrees with light winds out of the west and snow falling.
The outlook for Thursday and Friday.
Cooler, drier conditions are on tap for us the next two days. Temperatures should drop to around normal conditions for this time of year as a generally northwest flow develops. The next good chance of snow is Friday night as a short wave trough from the Gulf of Alaska enters our area. Avalanche conditions should improve somewhat as we dry out and temperatures get colder, but chances of triggering one will remain probable on slopes steeper than about 35 degrees.
Tip for the Day
During these stormy times make sure that you choose safe travel routes, such as ridgelines and low angle slopes. Also communicate with the group to make sure that everyone knows what the group is planning to do and feels comfortable with any decisions made.
Look for our next Advisory Saturday January 21st.
Please note that this avalanche advisory only applies to the backcountry and is based on limited number of observations in specific locations. Unanticipated weather changes such as a marked temperature increase or new snowfall beyond forecast amounts can increase the avalanche danger
01-23-2006, 04:03 PM #2