Avalanche Danger Is Not a Straight Line. Act Like It.

You’ve heard it a thousand times: “Check the avalanche forecast before you head out.” Good advice, but it’s incomplete. The real problem is that most skiers treat the danger scale like a speedometer—smooth, predictable, and easy to read. It’s not. The North American Public Avalanche Danger Scale has five levels—Low, Moderate, Considerable, High, and Extreme—but the danger between those levels doesn’t climb like a gentle slope. It jumps exponentially (Avalanche danger scale). That means the difference between Moderate and Considerable is far bigger than the difference between Low and Moderate. Skiers who don’t understand that are the ones who get caught.

Isn’t “Considerable” just a medium warning?

No. “Considerable” sounds almost benign, like “moderate” with a thesaurus. But at Considerable danger, natural avalanches are possible and human-triggered avalanches are likely (Avalanche danger scale). That’s not a warning—it’s a flashing red light. Most avalanche accidents happen at Considerable, precisely because skiers think it’s a “maybe” day. Treat Considerable as “conditions are primed for your mistake to become a slide.”

What does “High” really mean?

At High danger, travel in avalanche terrain is not recommended. Natural avalanches are likely, and human-triggered avalanches are very likely (Avalanche danger scale). That’s not a suggestion to pick your line carefully. It’s a directive: don’t go into avalanche terrain. Parks Canada goes further, strongly recommending that the general public avoid areas where the danger is HIGH or EXTREME, and that any travel be restricted to simple terrain or kept within ski resort boundaries (Avalanche danger scale (Parks Canada)). If you’re planning a backcountry tour and the forecast says High, cancel it. There will be other days.

Does High danger mean avalanches happen everywhere?

Not everywhere, but enough. High danger means avalanches are likely on many slopes, and the consequences of triggering one are severe. The danger ratings are provided for three distinct elevation bands (Avalanche danger scale). That means the danger can be High above treeline but only Moderate below. But don’t play a game of “find the safe slope” when the rating is High. The scale rates danger based on the likelihood, size, and distribution of expected avalanches (Avalanche danger scale). If the distribution is wide, even “safe-looking” terrain can bite. Keep it simple: High = stay out of avalanche terrain.

Is it safe to ski in-bounds during an avalanche warning?

Generally, yes, but know the difference. Ski resorts are responsible for managing avalanche risk within their boundaries. They use explosives, ski cutting, and closures to reduce danger. But in-bounds terrain can still slide, especially after heavy snow or wind loading. The NSAA’s Responsibility Code—first developed in 1962—tells you to stay in control and obey signs (NSAA Responsibility Code). If a roped-off area is closed, it’s closed for a reason. Don’t duck ropes. And if you’re skiing in-bounds during a High danger day, stick to open, patrolled runs and avoid steep, ungroomed shots that might have been skied but not bombed. The resort’s avalanche control is good, but it’s not perfect.

What’s the deal with “Extreme”?

Extreme is the red zone. At Extreme, all avalanche terrain should be avoided because natural and human-triggered avalanches are certain (Avalanche danger scale). Certain, not likely. You won’t find many people skiing backcountry on Extreme days, and those who do are either professionals or fools. The scale is categorical: avoid all avalanche terrain. That includes even low-angle slopes if they have terrain above them that could release. Stay home, or ski at a resort that has closed the dangerous terrain. Don’t be the exception.

Why do so many avalanche deaths happen at Considerable, not High?

Because people underestimate the exponential jump. At Considerable, human-triggered avalanches are likely, but skiers still go out. The statistics back this up: U.S. avalanche fatalities have stayed relatively stable at about 25 to 30 per year since 1995, despite an estimated 8-fold increase in backcountry use (Avalanche fatality trends (WEM/USDA)). That’s actually a success story for education, but the numbers are still too high. The reality is that most victims are experienced skiers who thought they could handle the conditions. The danger scale is not a suggestion; it’s a gauge. When it says Considerable, the snowpack is telling you it’s ready to slide if you make a mistake. Respect it.

Should I always check the forecast before a backcountry tour?

Yes, but don’t just check it—understand it. The avalanche.org partnership between the American Avalanche Association and the US Forest Service National Avalanche Center consolidates data from professional forecast centers (Avalanche.org education). That’s your first stop. But a forecast is a snapshot. Conditions change with elevation, aspect, and time of day. The scale gives danger ratings for three elevation bands, so read the details for the band you’ll be skiing. And remember: the danger increases exponentially between levels, so a jump from Moderate to Considerable is a big deal. Plan your route accordingly, carry a beacon, shovel, and probe, and know how to use them. The ICAR harmonized the international frequency for avalanche rescue beacons in 1989, fixing it at 457 kHz (ICAR avalanche rescue (ISSW 2004)). That means your gear will work with your partners’ gear—if you actually bring it.

What’s the single best move to stay safe?

Here’s my straight answer: avoid avalanche terrain entirely when the danger is Considerable or higher. That might sound extreme, but consider this: at Considerable, human-triggered avalanches are likely. At High, travel is not recommended. At Extreme, all terrain is off-limits. If you wait for “High” to call off a tour, you’re already late. The best move is to have a hard rule: if the forecast says Considerable or above, you don’t go into avalanche terrain. Period. That’s how you become the old skier who’s still skiing.

Bottom line

Treat the avalanche danger scale with respect it deserves—understand that danger climbs exponentially, not linearly. Check the forecast, read the details for your elevation band, and when it says Considerable or higher, stay out of avalanche terrain. That’s the single best move you can make.

Sources

• Avalanche danger scale - https://avalanche.org
• Avalanche danger scale (Parks Canada) - https://www.parks.canada.ca/pn-np/mtn/securiteenmontagne-mountainsafety/avalanche/echellerisque-dangerscale
• Avalanche fatality trends (WEM/USDA) - http://avalanche.org/wp-content/uploads/2018/07/17_WEM_Birkeland_etal_AvFatalities.pdf
• Avalanche.org education - https://avalanche.org
• ICAR avalanche rescue (ISSW 2004) - https://arc.lib.montana.edu/snow-science/objects/issw-2004-360-369.pdf
• NSAA Responsibility Code - https://www.nsaa.org/nsaa/safety/