Jackson, Wyoming - Whistler Blackcomb resort in British Columbia has stationed guards at the top of some areas to prevent skiers and snowboarders from entering hazardous terrain. Grouse Mountain resort, in North Vancouver, has suggested that government action may be needed to deter skiers and snowboarders from using off-limit areas. And Jackson Hole in Wyoming has already burned through nearly half of this year's budget for avalanche hazard reduction work, one month into the season.

Resorts throughout the western United States and Canada are struggling with avalanche hazards as weather patterns have created uncommonly widespread conditions of instability, wreaking havoc on mountains crowded with skiers of all levels at the start of ski season. Last week, avalanches at Whistler Blackcomb killed a snowboarder and a skier on terrain outside the resort's boundaries. On Wednesday morning, a controlled slide ran past Jackson Hole's $10 million Bridger Restaurant - already damaged by a recent avalanche - while the mountain was closed to the public.

"It's a war zone," said Lanny Johnson, a wilderness medical advisor and former patroller at Lake Tahoe's Alpine Meadows ski resort. He added that this avalanche cycle had "the best in the field scratching their heads."

Since Dec. 14, avalanches have caused 13 deaths in the United States and 23 total in North America - one in a roof slide and the others in skiing, snowboarding, snowmobiling and ice-climbing incidents, according to Dale Atkins, vice president for the avalanche rescue commission at the International Commission for Alpine Rescue.

Perhaps most troubling to resorts and safety officials is that three people died in-bounds - areas at resorts that are perceived as safe terrain. Avalanches in in-bounds areas have led to deaths of skiers at Squaw Valley in California, at Snowbird in Utah and at Jackson Hole. It is the most in-bound deaths in one season since three skiers were killed in a single avalanche at Alpine Meadows in 1976.

"One in-bound fatal avalanche in a season is unusual; three separate fatal incidents in one season is really rare," said Bob Comey, director of the Bridger-Teton National Forest Avalanche Center. "It's been a really big problem. We're doing what we normally do. Our techniques work really well, but they're not ever 100 percent guaranteed."

Early snow in the fall coupled with rain left a weak, ice-covered base on many mountains. Then heavy storms throughout the West dumped several feet of snow, which has been perilously resting on the vulnerable base.

"It is sort of like dominos covered by a board," Mr. Atkins said. "If dominos are widely spaced and a few fall over, nothing happens; however, if enough dominos are close to each other and one falls over knocking down others, enough may fall causing the board to collapse."

Avalanche forecasters anticipate that hazardous conditions could persist well into the season throughout the backcountry in the Rockies, the Pacific Northwest and the Tetons. The Teton County Sheriff's Department reminded the public last week - for the first time in its 17-year history - that search and rescue may be significantly delayed or unable to respond to backcountry incidents because of heightened avalanche hazards.

"We're off to a scary start; this December saw the most recorded avalanche fatalities for any December since the mining days," Mr. Atkins said, adding that, historically, January, February and March were the worst months for avalanches.

The conditions are so alarming that even many expert skiers who normally attack backcountry terrain with ease are staying within the controlled areas of resorts. Sales of transceivers, used to locate people buried in an avalanche, soared at Jackson Hole's ski shop after a recent in-bounds slide, according to J. D. Disney, a sales representative there. The beacons are typically carried by backcountry skiers, but Mr. Disney said the devices were purchased by many recreational skiers at the resort - including a woman who bought five for her family.

Grouse Mountain, which barred three skiers and one snowboarder indefinitely for using an off-limits, avalanche-prone area on its privately owned resort last week, said the provincial and federal governments may need to pass legislation in the interest of public safety.

Locals and visitors at Jackson Hole have been advised to stay out of the backcountry while the resort tries to keep the upper mountain open and safe. The resort budgeted $81,500 this season for avalanche hazard reduction tools that allow patrollers to trigger slides in a safe method, and Tim Mason, the vice president for operations, said patrollers may have already spent nearly half the year's budget in an attempt to keep as much of the upper mountain open as possible over the holidays.

This all comes at a time when global economic issues are already putting a strain on ski resorts.

"Resorts definitely rely on big weekends," Mr. Mason said. "Winter is our time of year. We count on those weekends, especially."

Mr. Comey said that another storm cycle was expected to hit the Tetons soon and that the amount of snowfall would determine whether avalanche conditions were exacerbated in the backcountry. The added weight of a heavy snowfall could trigger more slides. If it stops snowing, the snowpack may have a chance to stabilize.

"What we patrollers need more than anything else is a break," he said.

Chris McCollister, a 39-year-old ski patroller at Jackson Hole, can empathize. On Dec. 27, snow on an in-bounds slope shattered like a pane of glass under the weight of a local skier, David Nodine, and his companion, burying Mr. Nodine beneath roughly seven feet of snow. The patrol team had conducted avalanche hazard reduction work on the slope that morning, and it had already been skied. Squaw Valley and Snowbird had also conducted reduction work on their slopes before their in-bound fatalities occurred.

Two patrollers witnessed the slide and located Mr. Nodine's beacon within two minutes. They uncovered his head within another six. Patrollers quickly recovered him from a deep, concretelike tomb, but it was too late; he had suffocated.

Two days later, Mr. McCollister was on duty when he heard an emergency call over his radio: "The building's been hit," and, "there's workers buried." He immediately took the gondola to the resort's Bridger Restaurant, at 9,095 feet.

"I heard someone say multiple workers were down and that one person was definitely not recoverable," Mr. McCollister said.

A massive deep slab avalanche had rushed down the Headwall slope toward the resort's midmountain restaurant, partially pinning four patrollers on the outside patio, trapping a fifth and his search dog inside a nearby ski patrol room and knocking two more patrollers down the mountain's face.

Seven of Mr. McCollister's colleagues were hit by the slide. Everyone survived.

"It's been my most stressful year so far," said Mr. McCollister, who has been a patroller for eight years.

"I don't have trouble sleeping. I'm so exhausted. My only problem is waking up."