On Monday, Matt Tunseth, an out-of-work journalist in Anchorage, posted on his Facebook page a photograph of avalanche rubble on the flanks of the city’s most climbed mountain with a warning to friends that new snow and wind-loading had made especially dangerous the slopes of the Chugach Mountains.
Only two days later, three men were reported dead in an avalanche below Bear Point not far to the north in the Chugach. Bear Point is a 3,104-foot high point on a ridge that eventually climbs to the top of 4,271-foot Mount Eklutna.
Alaska State Troopers identified the dead men as 54-year-old Thomas Devine of Chugiak, 43-year-old Matthew Nyman of Colorado Springs, Colorado, and 50-year-old Edward Watson, of Miami. All were experienced in the mountains of Alaska.
Devine who lived in a suburb of the state’s largest city only miles southwest of where he died, was a former member of the board of the Alaska Mountaineering Club. He had in the past climbed Alaska’s 20,310-foot Mount Denali, the tallest peak in North America, and Washington’s heavily glaciated Mount Rainer, the 14,411-foot peak that looms over the Cascade Mountain range southeast of Seattle.
A decade-old story in the Alaska Star, his then local newspaper, described him as “part of a small group of Chugiak friends who spend their mornings climbing mountains when most people are just waking up to their cup of coffee.”
But Devine and the friends who died with him do not appear to have been on what mountaineers would consider a “climb” when they died on Tuesday. They were on more of what would be described as a “walk up” in a steep and narrow couloir, or gully, on the northwest face of the Bear Point ridge.
They appear to have tumbled hundreds of feet down that couloir to their deaths.
Alaska State Troopers blamed the fatalities on the lack of “PLB’s (personal locator beacons) or avalanche beacons,” though there is nothing to indicate either would have saved the men.
Avalanche beacons require that someone survive the avalanche and is then in a position to locate and dig out companions. All three men were reported to have been buried by the snow that thundered down the gully. If that report is true, none of them was in a position to look for others.
A similar problem applies to PLBs. If no one is able to turn the device on to call for help, it is a useless piece of equipment. And it remains unclear as to whether the men died from being buried in the avalanche or as the result of trauma suffered while tumbling down the gully amid blocks of snow.
Given the steep slope in the Bear Point gully, a drop down the gully of hundreds of feet, and the snow conditions in the Chugach at this time, an accident there would likely result in an avalanche victim being cartwheeled down a steep ditch while being pounded by blocks of snow.
An avalanche test pit dug near 2,000 feet in the Chugach on Wednesday revealed the snow breaking away in three layers of Labrador retriever size blocks of stiff snow that got harder as the dig went deeper into the snowpack.
The layers were separated by snow like sugar or what avalanche authorities call “faceted snow.”
“Weak layers involved in most avalanche accidents usually are a ‘persistent’ grain type such as faceted snow, surface hoar or depth hoar, but it can also be a layer formed within new snow such as low-density new snow or graupel,” notes Avalanche.org. “After an avalanche occurs, you often hear avalanche professionals ask, ‘what was the weak layer…'”
Avoiding avalanches, the site adds, is all about “knowing what is the weakest layer in the snowpack and how much stress it takes to make it fail.”
Some slopes in the Chugach now have weak layers that can come apart on their own, as Tunseth saw on days ago, or easily come apart under the weight of a human or other animal. And if the weak layer is under hardened snow on a steep slope, the hardened snow will start sliding and breaking apart as it does.
If something like this happened to Devine, Nyman and Watson somewhere near the top of the Bear Point gully they would have been doomed. The couloir is a classic “terrain trap,” a topographic feature that concentrates the sliding snow and thus increases the danger of an avalanche.
In this case, an avalanche near the top of the Bear couloir would have sent the men tumbling hundreds of feet down the gully amid a rain of snow blocks only to be buried near the bottom in the entire mass of however much snow released.
Norwegian avalanche investigators say most of the fatalities in avalanches in that country are linked to terrain traps. And Alaska has seen more than its share of such deaths.
Avalanche experts from the Chugach National Forest Avalanche Information Center are now investigating the Bear Point incident. A full report is expected eventually. The Center has been warning of tricky slab conditions for more than a week.
The Center’s forecasts are limited to the Turnagain Arm area of the Kenai Mountains east of Anchorage, but conditions in the Chugach Mountains just to the north are very similar to those in the Kenai Mountains at this time.