It hardly looks like anything other than a fun romp: a dog happily sticking its snout into deep snow, tail wagging in the air as the nose goes deeper and deeper. But for dogs trained in avalanche rescue, it could be a lifesaving mission.

Canines have become invaluable in many backcountry areas and at ski resorts, a role highlighted during what has been an especially deadly winter. Thirty-three people in the United States have been killed by avalanches since Dec. 18, according to statistics kept by the Colorado Avalanche Information Center. Its figures show that deaths this season (which typically extends from November to June) are on pace to exceed the modern record of 36 in 2007-08 and 2009-10. Over the past 10 years, an average of 27 people have died in avalanches in the United States.

The ideal dog for search and rescue is energetic, goal-oriented and playful. They come from a variety of breeds. Some, such as hounds, are gifted at tracking; others, such as Labrador retrievers, have a keen sense of smell and can search in minutes an area that could take humans hours.

With their heightened senses, trained rescue dogs can find “a bullet shell, a piece of plastic, a ballpoint pen or a set of keys,” said Scott Guenther, who works alongside his yellow Labrador, Nahla, with Jackson Hole Search Dogs in Wyoming.

Jackson Hole Search Dogs is a group of volunteer handlers who assist federal, state and local agencies in search and rescue missions year-round, providing dogs trained in trailing humans, as well as in wilderness searches for evidence, lost objects and water and cadaver searches.

If it bears the scent of a human, Nahla can find it. “I don’t find a cellphone every day, but I did find one that had been buried in snow for a week last year,” Guenther said.

Dogs are the best option when an avalanche strikes, especially if a victim is not wearing a beacon or has not turned it on. And the best dogs for the task are those who have a high prey drive, an expression that refers mostly to a dog’s level of excitement or motivation to perform a task in which time is critically important.

Although most avalanche victims are buried by an average of only three feet of snow, the prospects for survival become increasingly unlikely after about 15 minutes, according to Dale Atkins, a past president of the American Avalanche Association and a former forecaster with the Colorado Avalanche Information Center. Search and rescue teams work closely with local authorities, with dogs often at the forefront.

Nahla is 7 and has been with Guenther since she was “eight or nine” weeks old. Part of training her and other dogs involves marking an imagined avalanche area with flags, digging holes in the snow and placing old clothing in them for a few days. Then, “we put a couple of people in those holes, and we cut some blocks and plug them so they’re basically in an igloo,” hidden from the dogs but able to breathe and with a radio to keep in contact with trainers.

“Then I come along with my dog and say to her, ‘Hey, here’s your search area,’ ” Guenther continued. “I put my dog on her command to go search. Theoretically she knows to look for things underneath the snow that smell like people and she goes to work. When she finds that area of strong scent, she starts digging.”

Almost half of Nahla’s body may go into the snow, with her tail thrust skyward. Then she alerts Guenther by running to him and putting her paws on him. The idea is for a handler to not tip his or her hand, letting the dog offer all of the evidence.

“My dog digs in the snow and confirms with her nose. She’s like: ‘Oh, I know what you want. It’s right over here. It’s right here.’ So she’ll run over to me, jump on me and she’ll go back to that hole and keep digging,” he said. “That’s her way of saying: ‘Hey, silly, I know you saw me digging. Now I’m going to come over here and jump on you just to tell you, like, it’s right here.’ ”

Guenther and others look for “a dog that lives to do something — tug on a toy or catch a Frisbee or chase a ball. “You’re looking for a dog that 24/7 would chase that darn ball if you threw it all the time. That’s the dog that you can train to do just about anything in search.”

Nahla’s reward for a job well done: a game of fetch, which she loves.

“The way we work is that the dog is trying to find a person buried in the show, and they love that game. What they want is their toy,” he said. “They want to get to play, so everything about working with a search dog is about the game, about the reward, and the reward is the thing they just went for. My dog will play fetch until her legs fall off.”

There is not a national standard for training and certifying wilderness rescue dogs, according to Stephanie Thomas, executive director of the Teton County (Wyo.) Search and Rescue Foundation. Several organizations offer seminars and varying levels of certification for dogs across multiple specialties and regional groups. Guenther and Nahla, for example, are certified to have met a set of standards agreed upon by members of Tri-State K-9, which has grown to include chapters in seven Western states.

Roy Pescador, president of the National Search Dog Alliance, echoed Thomas but said his organization has evaluators who, upon request, can test dogs for avalanche and other types of rescue training under general FEMA guidelines for its National Incident Management System. Most handlers and their dogs also work with sheriff’s departments and other local authorities who have standards.

At the Crystal Mountain Resort near Mount Rainier in Washington, Kim Haft of the ski patrol has worked with Darwin, a 9-year-old Nova Scotia duck tolling retriever, since he was eight weeks old. He and other rescue dogs at Crystal Mountain, Stevens Pass and Alpental resorts are tested with timed searches and certified by handlers.

“Some of the resorts — in Whitefish, in Montana, Mount Bachelor in Oregon — they all have their own avalanche rescue dog programs,” Haft said. “That being said, we are part of a larger network of avalanche rescue dogs through Washington state where we will go into the backcountry and try to help recover bodies.”

The need to train dogs for recovery missions does involve a grisly requirement: cadaver parts. If meat were used to train dogs to find bodies, they could confuse that scent with those left by wild animals. Guenther tells the story of one man who was happy to donate a finger he had lost in a table-saw accident. Other sources are from people who donate their remains posthumously.

Still, the thrill of the hunt motivates the dogs. When a call comes in, for Guenther and Nahla, “she knows the special toys that we use when she’s going to work. We say, ‘Want to go to work?’ and, holy cow, you ever see a dog light up?” Guenther said. “They get so excited because for them going to work means going to play. Their goal is to find the thing they’re looking for, and they look you in the eye like, ‘Bring on the toy, baby.’ ”

The results can be remarkable, even when they’re not related directly to a rescue. On a missing-person search mission four years ago in Colorado’s Mesa Verde National Park, Nahla got the chance to show how talented she is when she sniffed out human remains in the park’s ancient pueblo dwellings. Guenther was briefly baffled.

“In this pile of dust, basically all that was left of the human remains,” Guenther said. “But my dog, alerted to look for a human, found one that was basically there for a thousand years.”

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