The Avalanche Review, VOL. 6, NO. 4, MARCH 15, 1988
Copyright © All Rights Reserved; AAA
Hazard Catagories in Europe
by Bruce Tremper
Avalanche hazard catagories are one of those things thats sure to start a fight. Some people have grown dependant on them. Some people want to throw them out. Almost everyone misunderstands them.
So maybe we can turn to the Europeans for some help. After all, they have been at this for the last 50 years. And that's exactly what I did last summer when I was there. It turns out that we're just in luck because all the European countries got together last season and attempted to come to some consensus on the ever thorny subject of avalanche hazard categories.
They, being more civil than us, did not come to fisticuffs as nearly happens in this country when avalanche people bring up the subject. But from the sounds of it, there's probably a brighter prospects of eliminating nuclear missiles worldwide than the chances of European countries coming up with consistent avalanche hazard categories.
Each has their own system. Each thinks it's the best. Each system has ponderous historical precedence behind it. Turns out they couldn't even agree on what parameters to characterize, much less how to characterize them.
For example, the Swiss--who have been at this business the longest--have 7 non-linear hazard categories--4 describing degrees of localized hazards and 3 for widespread hazards (see accompanying table).
The French, also have 7 nonlinear categories, however they separate them into categories of "accidental risk" (human triggered avalanches) and "natural risk" (spontaneous avalanches) (see accompanying table).
And so on.
To understand why they have so many categories when North Americans usually use only 4 (low, moderate, high and extreme), you must realize that they have a long history of large catastrophic avalanches descending into villages and highways. Therefore, they must not only forecast for the catastrophic avalanche but also for the smaller, but just as dangerous, human triggered slides. North Americans, on the other hand, usually leave forecasting catastrophic avalanche to the highway and railroad control teams. Our forecast centers concentrate on the human triggered avalanches, which claim the vast majority of North American lives (which has also become the case for the last 30 years in Europe).
So as you can see, there's no easy answers--no right ones, no wrong ones-just different ways of looking at the same thing. If nothing else, it's nice to know that the neighbors fight about the same things we do.