Good afternoon this is Eric Knoff with the Gallatin National Forest Avalanche Center with an early season Avalanche Information Bulletin issued at 4 p.m. on Thursday, November 12th. Jeff King of Edward Jones in cooperation with the Friends of the Avalanche Center sponsors this bulletin.
Welcome back winter! Southwest Montana has become the epicenter of a strong cold front passing over the Northern Rockies. This front has delivered widespread precipitation with the Bridgers and mountains around Cooke City receiving the most with 12-16 inches of snowfall. Accumulations in the Northern Gallatins were eight to ten inches with West Yellowstone measuring around six inches. As this strong upper level trough is pushed to the east, we can expect snowfall to taper off this evening. Clearing skies and colder temps will prevail through mid-day Friday with another round of moisture moving into the area late Friday night into Saturday. Saturday night into Sunday should stay dry with below average temps.
November in Southwest Montana always seems to offer up a variety of conditions. Over the past few weeks I have talked to people who have participated in a wide range of outdoor activities varying from ice climbing and skiing to rock climbing and road biking all in the same day. Cold temps in the higher elevations have preserved the existing snowpack on northerly aspects above 8,000 ft. These north facing slopes have become weak and faceted creating a very unstable base for the new snow to fall on.
In the past 24 hours, over a foot of high density snow has fallen in most areas. This rapid load on a weak snowpack has created the perfect recipe for avalanches. Yesterday I climbed the North Face of Sphinx Mountain south of Big Sky. Check out a photo at:
http://www.mtavalanche.com/images/09/north-face-sphinx-mountain-11-nov-09
Check out a short video at: http://www.youtube.com/watch?v=Oyf-GNskE6o
I experienced extremely windy conditions on south and west facing slopes, but found calmer and snowier conditions on the north face. The most snow I encountered was on mid elevation slopes protected from the wind with a N to NE facing aspect. These slopes held 18 inches of snow and were comprised mainly of wind slabs sitting on top of six inches of facets. Due to the fact that most north facing slopes in the forecasting area hold similar conditions, I would avoid traveling on steep, north facing slopes in the days to come since they could avalanche. Already this season there have been multiple natural and human triggered avalanches resulting in close calls and minor injuries. Preseason conditions exist, so be careful of rocks, stumps, and other obstacles under the snow. Before heading into the backcountry make sure everyone is carrying avalanche rescue gear and be sure you know how to use it.
A SPECIAL CAUTION TO HUNTERS
Since many hunters travel solo, do not carry avalanche rescue gear and focus their energies on game instead of snow, they are susceptible to getting caught in a slide. It's not unusual for hunters to trigger avalanches this time of year. Be wary of crossing any wind-loaded gullies and avoid avalanche terrain which is any snow covered open slope steeper than 30 degrees.
We will send out Avalanche Information bulletins as conditions warrant. In the meantime, play it safe and don't get injured! We're always interested in your backcountry observations so drop us an email at mtavalanche@gmail.com or leave us a phone message at 587-6984.
TWITTER/FACEBOOK
Follow us on twitter.com/avalancheguys and Facebook under Friends of the Gallatin National Forest Avalanche Center: http://www.facebook.com/pages/Bozeman-MT/Friends-of-the-Gallatin-National-Forest-Avalanche-Center/173768210029?ref=ts
AVALANCHE EDUCATION
We're busy taking reservations for our avalanche classes. We've already scheduled the Basic Avalanche Awareness class at MSU on Dec 2,3&5. Snowmobile Awareness classes are offered Dec 2,3 &8 in Bozeman and Dec 17&18 in West Yellowstone. Check out our classes at http://www.mtavalanche.com/education2/index.shtml
If you would like to schedule a class you can drop Jay Pape (Education Coordinator) an email at friendsofgnfac@gmail.com