Friends of the Flathead Avalanche Center Hi Chuck Savall and Steve Kuijt. Thanks for the comments. These are good points and we want to address them. We full-heartedly agree that experts and novices alike can all succumb to avalanche accidents. We aren't trying to model poor behavior so we want to explain our decision making and protocols for avalanche investigations, which is a part of our work as avalanche forecasters.
First, the objective of our visits to crowns is to document the snowpack structure and assess the timing, and thus weather parameters, that led to the avalanche release. Our center uses deep slab forecasting tools that rely on weak layer and structural characteristics. Our goal is to be able to accurately predict events like this, as we successfully did on Saturday, when we raised the danger to High and issued a Special Avalanche Bulletin for the Flathead Range.
Second, the mechanism for avalanche failure for a deep slab is the collapse of a weak layer. In this case, it is clear that the layer collapsed across the entire slope already, including the hangfire that didn't slide. I encourage you to read this paper, which describes how sintering of a weak layer after collapse causes a weak layer to strengthen about 15 times faster than a layer that hasn't collapsed.
https://agupubs.onlinelibrary.wiley...../2005GL025104 It may seem counterintuitive, but after 12 hours or so, a slope that has already collapsed and avalanched is actually significantly stronger than a neighboring slope that hasn't collapsed:
Third, we are careful to wait for periods of improved stability and stable weather before conducting crown profiles like this, and we choose locations that aren't threatened by lingering concerns of cornice falls, sluffs, etc..
Lastly, we are careful not to travel on the hangfire itself, as a safety precaution. We acknowledge that there is a certain amount of risk that we accept in conducting daily fieldwork in avalanche country, just as there are other occupations in the public safety realm, such as firefighters, police officers, or search and rescue, that also accept risk with the ultimate goal of enhancing public safety. We attempt to minimize that risk at our forecast center through a series of peer-reviewed fieldwork plans, safety protocols and gear, and continued professional development and rescue training.
