Ever wonder how the snow on north aspects can stay cold and dry during such warm weather? There is a big difference between air temperature and snow surface temperature. This is why the snow can refreeze even on relatively warm nights if the skies are clear. Snow loses heat very efficiently to clear skies at night then warms during the day as air temperatures warm. See the graph below showing air temperature vs snow temperature along Bunnells Ridge (8800') just south of Provo Canyon during the last 2 days. Notice that snow temperatures at night got as low as 6 degrees F …

Not long ago, I was invited to give a talk on any subject of my choice to aLevel 3 avalanche class with the American Avalanche Institute. The owners of AAI and I haveknown each other for 15-20 years. They should have known better. So. The night before, I had the Level 3 participants - all experiencedsnow and avalanche professionalsin their own right - think of a time when an avalanche surprised them. The next morning, I began by showing them a clip of risk reduction researcher Gordon Graham talking about what he calls High Risk, Low Frequency events. You should watch …

When I wrote the blog on the effectiveness of avalanche airbags, I was surprised that most of the comments revolved around risk homeostasis. So what the heck is risk homeostasis? Let me tell you a little story…. I was just a youngster, around 5 years old, at the family cabin on Flathead Lake in Montana where we spent all our summers growing up. My mother had just purchased a newfangled substance—mosquito repellent—and she sprayed it on my exposed skin and explained that the “buggies wouldn’t bite me anymore.” Wow, I remember …

Backcountry Responsibility Objective from Trent Meisenheimer on Vimeo. With the freedom of the hills comes responsibility. Social responsibility in avalanche terrain is critical as backcountry use explodes. Establishing a clear set of expectations andshapinga culture of responsibility around Knowledge, Awareness, and Wisdom is imperative to protect not only ourselves and others...but our continued access into backcountry terrain. Drew Hardesty Thanks to Trent Meisenheimer, the UAC, TGR, and others for their hard work and support. Interview with TGR - ARE THESE …

Traumatic injuryamong avalanche victims has received increasing attention since 2009 when a Canadian study reported a surprising 25% of victims died of trauma. Previous studies suggested trauma as a cause of death occurred in less than half that number. Whatever the number, trauma is often a factor for both victims and survivors. A significant proportion of avalanche trauma mortality is attributed to head and cervical injuries. The intuitive response has been to advocate for protective strategies, including helmets. I have recently published a commentary on this topic …

Because of the recent, tragic fatality on Gobbler’s Knob, the Utah Avalanche Center has received many questions about the effectiveness of avalanche airbags. The skier caught in the avalanche deployed their airbag but died anyway. So what gives? Here’s the short answer followed by a quick primer on avalanche airbags and where the statistics come from: Answer: According to the latest, peer-reviewed, statistical study, a deployed avalanche airbag will reduce mortality by 50% (22% vs. 11% in the study). But because 20% of the people in the dataset were not …

Avalanche travel decisions are about risk vs rewards and penalties – we use an assessment of hazard to choose how to satisfy our desires without realizing our fears. The traditional focus is on assessment and management of the risk side of the process and assumes that the reward side is a fixed entity, but it is also possible to influence choices by altering the perception of reward. Choices are driven by our desires and our desires can be manipulated, either by external influences or by a deliberate choice to alter our desires. The traditional view of risk …