The use of the North American Danger Scale has a fair bit of nuance to it.  Some people tend to get distracted by the “likelihood” verbiage especially when it comes to understanding the difference between Moderate and Considerable danger. In considerable danger ratings we see a “possible” naturals and a “likely” human trigger.   

It is likely we will trigger an avalanche during considerable—this seems like it would be pretty risky to go into avalanche terrain under these circumstances.  However, not all avalanches are the same and we need to consider a more nuanced understanding of the danger rating tool.  We find this in the “size and distribution” guidelines.

Two pathways to considerable

There are several pathways to considerable danger as far as the size of the avalanches are concerned.  And the size is the key in really understanding the ultimate risk to our persons.

If we are seeing “large D2 and very large D3” in “specific or isolated” areas this is pretty spooky.  These are large enough avalanches to be extremely dangerous to a human.  This is the common setup we find associated with may persistent problems or larger snowfall events. 

However, there is another pathway to considerable.  “Small avalanches in many areas”. If we have the potential for 10 inch storm slabs happening on most all slopes around 40 degrees we could also see a considerable danger rating.  These avalanches are quite manageable for an experienced operator in a lot of terrain.

With “very large/D3” avalanches we are playing Russian roulette with a revolver.  But with “small/D1” avalanches we are more playing Russian roulette with a bb gun and pointing it at a knee.  Yes, they are both avalanches but understanding the consequence of the two events is far more important than the likelihood. 

Size matters and terrain matters

In many ways, understanding the consequence is more important than the likelihood.  Smaller snow volumes coupled with a good understanding of terrain allows for an experienced operator to step out into larger terrain in a very reasonable manner.

In Colorado this is primarily related to:

1. Not being where there is a reactive persistent structure (dangerous snow)
2. Not being in terrain where a small slab that couldn’t burry could still send you into a dangerous sliding fall (dangerous terrain)

This more nuanced understanding of avalanches will allow us to expand the amount of terrain we can operate in when we have good snow to ski.  Because ultimately, lots of good power is inevitably associated with increased avalanche danger.

It’s all about consequence 

The reality is, if we want to ski steep terrain in powder we will encounter avalanches.  We must accept that fact and learn to manage the nuance of that reality.  We must begin assessing consequence effectively and in a fashion that prevents us from getting killed.  But the reality is we cannot expect to ski steep terrain in powder with no risk at all.

There are three main categories of consequence I use in decision making:

1. non avalanche terrain
2. avalanche terrain and problem type that can’t kill me
3. avalanche terrain and problem type that can kill me

Approaching our interaction with the mountains from this perspective I find to be much more practically useful than simply asking can and avalanche happen. Of course, we need to get good at this consequence assessment as well.