Good morning. This is Karl Birkeland with the Gallatin National Forest Avalanche Advisory issued on Friday, March 13th, at 7:30 a.m. Island Park Adventures and Yamaha Snowmobiles, in cooperation with the Friends of the Avalanche Center, sponsor today’s advisory. This advisory does not apply to operating ski areas.
It’s going to be another mandatory day for sunscreen in the mountains. Expect sunny skies and westerly ridgetop winds at about 20 mph. Mountain temperatures are currently in the teens, but will warm up into the mid-30s. By late tomorrow clouds should start increasing, with our next chance for precipitation coming on Saturday night and into Sunday.
The Bridger, Gallatin and Madison Ranges, the Lionhead area near West Yellowstone, the mountains around Cooke City and the Washburn Range:
My partners and I headed into the southern Madison Range in the Bacon Rind drainage area yesterday. What we found will not surprise our regular readers. We dug several snowpits on aspects varying from southeast to northeast and elevations between about 8500 to 9000 feet. While some snowpits showed quite stable conditions, other pits continue to clearly demonstrate lurking instabilities. Stability tests that fracture are taking quite a bit of force to do so, meaning that triggering an avalanche is becoming more difficult. Still, once fractures are initiated, our tests suggest they are capable of propagating and triggering avalanches. In one pit we also found some buried surface hoar about 2 ½ feet below the surface. We have not seen this layer in any other recent pits, so I’m guessing this was an isolated pocket, but it was still enough to concern us. Given the conditions, we only felt comfortable skiing slopes less than about 35 degrees. You can watch a video of one of the more unstable test results we found here:
http://www.youtube.com/watch?v=rwXW7NIzlBo
Doug and his partner rode into the Lionhead area near West Yellowstone on Wednesday. Their observations are indicative of the avalanche conditions we have right now. They rode a lot of miles, but saw only two avalanches. Still, those two avalanches propagated for large distances, demonstrating that our weak layers might not be able to be triggered everywhere, but where you can trigger them they are capable of producing sizable and dangerous slides. Photos of these slides and a video of the snowpack in the Lionhead area can be seen at:
Photos: http://www.mtavalanche.com/photos/photos.php
Video: http://www.youtube.com/watch?v=pGZmmPnTROQ
We had a couple great reports from the backcountry around Bridger Bowl. On Wednesday afternoon a person triggered a 1 foot deep wind slab near the ridgetop on Saddle Peak, but was able to ride off to the side and avoid being caught. The slide ran about 200 to 300 yards down the slope. Yesterday some experienced skiers backed off some terrain north of the ski area after finding wind slabs up to three feet deep that “just didn’t feel right”. These observations show that backcountry conditions still exist in spite of all the traffic outside the ski area boundary.
For today I’d call the avalanche danger MODERATE, meaning human triggered avalanches are possible. However, avalanche conditions like these make me nervous. The probability of triggering an avalanche is continuing to decrease, meaning that many slopes can be safely played on and you are bound to see tracks in many areas. However, I’m confident that there are still a few slopes out there where a skier or snowmobiler could trigger a sizable slide. The best approach is to carefully evaluate any slopes you are planning on riding. If you don’t take the time to evaluate the slope, you might want to remember the immortal words of Clint Eastwood’s Dirty Harry: “You’ve got to ask yourself one question: Do I feel lucky?” And, don’t forget that today is Friday the 13th.
WET SNOW AVALANCHES
Spring is here and the sun is beginning to affect our southerly facing slopes. Most of these stayed dry yesterday except in a few places with thin snowpacks and plenty of rocks. With today’s warmer temperatures and sunshine, a few isolated southerly facing slopes may start to get wet enough to produce small wet slides.
UPCOMING EVENTS
Make plans to attend the 28th Annual Pinhead Classic Telemark Festival tomorrow at Bridger Bowl. This year’s theme is “The Olympics” with events for all ages and all abilities. Prizes are awarded for everything but the fastest time and all proceeds benefit the Friends of the Avalanche Center. A registration fee of $30 gets you a ½ -day rate lift ticket, t-shirt, commemorative pint glass, multiple laps on the dual slalom course, numerous prizes and awards, and dinner, dancing, unlimited beverages, and live music at the Emerson that evening. Visit www.pinheadclassic.com for more information.
Mark Staples will issue the next advisory tomorrow morning at 7:30 a.m. If you get out in the backcountry give us a call or send us an email with your observations. You can reach us at 587-6984 or at mtavalanche@gmail.com.
