Girdwood residents warned to watch for roof avalanches/Craig Medred photo

Just about this time last year, the Kenai Mountains claimed the life of 29-year-old Tyler Kloos in an avalanche, and on Thursday Chugach National Forest Service officials were warning of danger building again on the slopes south of Alaska’s largest city as winds blew, temperatures warmed and rains fell.

The unwinter-like weather is the result of Pacific Ocean storms being pushed north as the polar vortex decays and a ridge of high-pressure air forms along the North American West Coast.

Hurricane force winds and rain slammed into the 49th state’s underbelly starting late Wednesday. Anchorage Hillside temperatures peaked at 45 degrees on Wednesday night.

Winds atop Sunburst – a peak above the Turngain Pass in Kenai Mountains – to 98 mph, the Chugach National Avalanche Information Center reported Thursday.

Those sorts of winds blow around a lot of snow and deposit it on the leeward sides of mountain ridges. As the snow piles up in big slabs, the weight of it steadily increases and avalanche dangers increase.

“Portage Valley and Girdwood have received the highest amounts of precipitation and storm slabs could range from two- to three-plus feet in these zones,” the daily avalanche report said. “In Turnagain Pass where less snow has fallen storm slabs are expected to range from eight- to 16-inches thick.”

That might not seem like much snow, but the center noted there is still significant danger:

“If you head to an area that received less snowfall please keep in mind that a triggered slab today could still be large enough to bury or kill a person.”

In the Portage and Placer rivers valleys at the head of Turnagain Arm, the report added a warning that “heavier rain and snowfall rates have occurred and large avalanches above treeline may send debris to sea level and over summer hiking trails such as Byron Glacier Trail.”

Bad history

Alaska has in recent years suffered several fatalities when relatively small avalanches swept people into narrow gullies or other terrain traps and buried them there.

Above 1,500 feet, the avalanche center has classified the avalanche danger as high. It was judged “considerable” at lower elevations with the caveat that “wet loose snow avalanches are possible.”

Turnagain Pass on the Seward Highway tops out at 900 feet. It is a popular destination for both backcountry skiers and snowmobilers. The ridges to either side rise to 2,500 feet and more.

Seattle Ridge to the north of the highway was the scene of the state’s deadliest recreation-related avalanche in March 1999. A massive, half-mile-long slab of snow broke seven-feet deep near the top of the ridge and swept to near the valley floor.

Dozens of snowmachine riders were in the area at the time. Most managed to escape, but as avalanche experts Doug Fesler and Jill Fredston later reported, “six snowmobilers were killed, three injured, one was partly buried but uninjured, at least five others were dusted as they tried to escape, and nine snowmachines were destroyed or damaged.

“An unknown number of other snowmachiners (six to 12, estimated) narrowly escaped.”

The search for bodies went on for days as troubled family waited for bodies to be found.

The deadly slide had been preceded by several smaller slides, two natural and one triggered by snowmachine hill climbers on the steep south face of the ridge. The big avalanche hit at about 4 p.m.

Fesler and Fredston concluded that it was “most likely  triggered by highmarkers trying to reach the top of the mountain.

“Ken Seagle was just within the southern flank of the fourth slide in the process of hill-climbing (about half way up), when he looked over his shoulder and saw the whole mountain to the north avalanching. He turned his machine and rocketed toward the debris of the earlier slide in a successful attempt to escape. He said he was traveling at speeds of approximately 50 mph over debris blocks four to five feet in size, causing him to become airborne approximately 75 percent of the time.

“To his right (north), approximately half way up the mountain, was Dan Demers, who” was stuck and digging out his snowmachine. He did not survive. The avalanche tumbled him about a third of a mile downhill and buried him.

His snowmobile was spotted partly visible in the avalanche almost as soon as the snow stopped moving, and people with probes to find him and shovels to dig him out were on the scene almost instantly.

They located his body after only a minute or two of probing, but it took more time to free him from under three to five feet of snow. He was unconscious when pulled out of the snow. A nurse who was on the scene started CPR but could not revive him.

Avoidance first

Smart mountain riders and backcountry skiers now all carry probes and shovels, and wear beacons and often air bags, but the best way to survive avalanches is to avoid them.

A 2009 review of  204 avalanche fatalities over about two decades concluded that about a quarter of all deaths are due to trauma.

A Seattle Ridge repeat remains among the worst fears of Alaska avalanche experts, but they were warning of plenty of other avalanche dangers Thursday including “roof avalanches” in the ski community of Girdwood where the poor design of some buildings leads them to dump snow where people walk.

“Pay attention to children and pets and where you park your car,” the avalanche report said. A four-year-old girl from the community of North Pole died only two years ago after a metal roof avalanched on her when she walked outside. 

A Girdwood-based avalanche technician for the Forest Service died in 2004 when  he walked out of a Forest Service work center in Portage only to be hit by an estimated 650-pounds of ice and snow cascading off a metal roof.

The weather now hitting Alaska is expected to keep avalanche conditions problematic into the weekend.

Another storm was rolling into the region with heavy rain expected through Friday morning below 2,500 feet with heavy snows above.

The forecast calls for the rain to stop by Saturday but daytime temperatures are likely to remain above freezing. Snow moves in Sunday.

The CNFAC forecast is updated regularly, but recreationists should remember it’s an area forecast. Dangerous pockets of snow can exist even when conditions are moderate. People who plan to venture into the backcountry should learn how to assess avalanche dangers.