A pack of backcountry skiers hustle to a clump of snow, beckoned by the increasing frequency of electronic beeps from the transceivers strapped across their chests. These beacons can both receive and send signals within a radius of 40 to 50 meters, helpful for finding comrades buried by avalanche.

Rescuers typically have about 15 minutes to reach an avalanche victim before he or she dies of asphyxiation, responsible for 75 percent of avalanche-related deaths. Trauma accounts for the rest.

“There’s no time to call 911,” said guide Aaron Ball.

A probe, which looks like a segmented tent pole, is poked into the snow bank to find the victim. The less snow to dig, the better because the average avalanche victim is buried in nearly four feet of snow.

That amount of shoveling “kills time and can kill you,” said Ball, an instructor with Southwest Adventure Guides during a recent avalanche rescue training exercise at Molas Pass near Silverton.

Fortunately, no one on this day had to worry about death because their “avalanche victim” was a backpack buried by a student while the others were not looking. Nationally, avalanches already have killed 11 victims, including four in Colorado, this winter. The state appears to be on pace for meeting its average of six avalanche-related deaths per year.

Midwinter is a deadly time because new snowfall is let loose on older packed snow. People are prone to “powder fever,” or the rush to get to untracked snow.

Aware of the perils, including triggering their own snowslide, outdoor recreationists who prefer to play in the backcountry are packing local avalanche training classes. Jeff Kling, owner of Kling Mountain Guides, said he often has a waiting list for his classes.

Avalanche instructors attribute the growing popularity of avalanche training to advances in sporting equipment making the backcountry more accessible for snow sports recreation.

A backcountry snowboard, or a split board, for example, can be split into two skis to make it easier for uphill trekking.

New York native Russell Altman, 27, loves to ski the backcountry because “there’s less people, better snow.”

He likes going where “humans are not supposed to go.”

As a “professional ski bum” on a three-month ski trip, Altman often sleeps in the back of his Humvee. He decided to take an avalanche training class because he realized there’s a lot “I don’t know.”

After enrolling with Southwest Adventure Guides, Altman was surprised that many of his fellow students would bother coming to Durango because many were from other popular ski areas, such as Jackson Hole, Wyo.

Avalanche training is a local niche industry because an active snowpack makes it an ideal place for study, Kling said. Snowfall in Southwest Colorado tends to be intermittent as snow from early in the season is not replenished until a midwinter storm. As new snow totters atop an old and unstable snowpack, conditions become ripe for slides.

“It’s just the way our snowpack sets up,” Kling said. “It doesn’t matter how strong the third floor of a house is if you have a weak foundation.”

Courses can teach shoveling techniques, the technology of transceivers and how to dig an avalanche pit and interpret layers of snow such asgeological formations.

The point of the classes is to become savvy enough about the terrain so students don’t have to rely on their transceivers and buddies for rescue.

Kling said his students can become proficient enough to know that the “100 feet to the left is really sketchy, but 100 feet to the right is totally safe.”

One rule of thumb is that slopes less than 25 degrees or steeper than 60 degrees tend to be safe. Of course, slopes between 30 to 40 degrees typically are more popular for skiing.

Avalanche instructors said backcountry travelers are more often threatened by human nature than Mother Nature.

Powder fever can lead the most experienced backcountry skier into making foolish mistakes.

“Ninety percent of all avalanche accidents are related to human factors,” said Mark Allen, an instructor with Southwest Adventure Guides, based in Durango.

Since he took his avalanche training in 1994, Allen has seen the emphasis change from the science of snow to the fundamentals of good decision-making.

Ian McCammon, in an article for Avalanche News, identified common mistakes that backcountry travelers make, such as complacency about familiar terrain, men showing off to women and “expert halo,” or misguided confidence in a leader.

Tom Murphy, spokesman for the American Institute for Avalanche Research and Education, urges common-sense precautions, such as reading the latest avalanche forecasts from the Colorado Avalanche Information Center at www.avalanche.state.co.us.

But the most important thing to do is to stop and think before heading into the backcountry.

“When you are talking about life and death, there needs to be some analysis,” said Murphy. “If you’re uncertain, stay off.”

jhaug@durangoherald.com