Good morning. This is Eric Knoff with an early season avalanche information bulletin issued on Monday, November 28 at 7:30 a.m. This bulletin is sponsored by the Yellowstone Club Community Foundation in partnership with the Friends of the Avalanche Center. Please remember that uphill traffic is not allowed at Big Sky or Moonlight Basin Ski areas. Uphill traffic is permitted at Bridger Bowl, but backcountry snow conditions do exist. Doug will issue the next bulletin on Wednesday morning.
A developing cold front has replaced yesterday’s warm-sunny weather with cloudy skies and slightly cooler temperatures. Currently mountain temperatures are ranging from the mid 20s to low 30s and winds are out of the WSW at 15-30 mph. As the cold front moves through the region this morning, we can expect a chance of mountain snow and valley rain with accumulations of one inch possible in the higher elevations. A ridge of high pressure will build behind the cold front producing partly cloudy skies and drier conditions by this afternoon. Highs today will be in the mid 20s to low 30s in the mountains and winds will stay out of the WSW at 15-30 mph.
The past week has been rather uneventful in terms of weather, which has been both a blessing and curse for the snowpack. On the negative side, warm temperatures and lack of significant precipitation has done little to improve riding conditions. However, the snowpack has had time to adjust and heal, helping the pack strengthen in parts of our forecast area. Unfortunately, there are still portions of our advisory area with concerning issues.
The two zones with the deepest snow cover - the mountains around Cooke City and the northern Gallatin Range - have a layer of well developed facets at or near the ground that are still producing both natural and human triggered avalanches (video). This problematic layer can be found on all aspects and elevations and it is buried too deep in most locations to be affected by warmer temperatures (snowpit).
Over the past two days, Doug and Mark have been riding in the Cooke City area collecting snowpack data and documenting avalanche activity (photos). They observed multiple avalanches and noted the most likely areas to trigger a slide would be in wind loaded terrain or on steep slopes where the snowpack is thinner. This is also the case in the northern Gallatin Range.
The rest of our advisory area, which includes the Bridger Range, northern and southern Madison Ranges, the southern Gallatin Range and Lionhead area near West Yellowstone, have thinner and slightly stronger snowpacks. Over the past four days I have skied in Bacon Rind, the Lionhead area and in Beehive Basin. I have been encouraged by stability test scores and observed little in the way of avalanche activity. However, it is still possible to trigger slides in these areas. Steep-upper elevation slopes, specifically those that have been wind loaded will be the most likely to hold unstable snow. Be cautious if you are traveling in this type of terrain.
Doug will issue the next bulletin on Wednesday morning.
We will begin issuing avalanche danger ratings when start daily advisories. For now - any snowpack or avalanche information is especially valuable. If you get out, please drop us a line at mtavalanche@gmail.com or leave us a message at 587-6984.
Wednesday, November 30, BOZEMAN
Introduction to Avalanches with Field Course at MSU. Wednesday and Thursday evening lectures with a field course on Saturday. More info at http://www.mtavalanche.com/education/classes/workshops
Tuesday, December 6th Beartooth Harley, Billings – Basic 1 hr Avalanche Awareness
More info at http://www.mtavalanche.com/workshops/calendar
Tuesday, December 6th 406 Brewery, Bozeman – Basic 1hr Avalanche Awareness
More into at http://www.mtavalanche.com/workshops/calendar
Wednesday, December 7th, REI Bozeman – Basic 1 hr Avalanche Awareness
More into at http://www.mtavalanche.com/workshops/calendar
Wednesday, December 7th Livingston - Snowmobiler Introduction to Avalanches with Field Course, Wednesday and Thursday evening lectures with a field course on Saturday. More info at http://www.mtavalanche.com/education/classes/workshops
Thursday, December 15th West Yellowstone – Snowmobile Guides Course. Lectures on Thursday - field day on Friday. More info at http://www.mtavalanche.com/workshops/calendar