Published: Friday, January 4, 2008
Avalanche risk unusually high
Recent deaths highlight mountain danger
By Jackson Holtz, Herald Writer
Fatal beauty.
That's what experts call the vast fields of mountain snow that have grown dangerously deep and unstable in Western Washington during one of the snowiest seasons since records have been kept.
A combination of weather, wind or extra weight -- including hikers and snowmobiles -- easily can trigger deadly avalanches.
That's what officials say happened when an Everett woman, 43, died New Year's Day snowmobiling north of Mount Baker. The same thing occurred when a Brier man, 22, died snowshoeing on Mount Rainier before Christmas.
Nationally, a dozen deaths so far this season are blamed on avalanches. Eight of the deaths have been in Washington.
The winter storms that pummeled the mountains in December set up conditions for extreme avalanche danger. Experts predict it will only get worse.
"We've had several classic events that create avalanche dangers," said Kenny Kramer, an avalanche meteorologist with the Northwest Weather and Avalanche Center.
The risk is going to increase with more snow and high winds forecast for the weekend. People can enjoy the snow-covered backcountry, but they should be prepared with knowledge and the right equipment, Kramer said.
The early December storms that caused widespread flooding built up a snow base that formed a thick ice crust after temperatures warmed and freezing levels rose, Kramer said.
Snow falling on that ice has a weak bond and "the last half of December has just been nonstop snow," he said.
At Stevens Pass on Tuesday, measurements showed snowfall at 94 inches, nearly 8 feet deep. That's 152 percent of normal for this time of year, National Weather Service meteorologist Andy Haner said.
"It was a very snowy month up in the mountains in both the Olympics and Cascades," he said.
December ranked among the top five snowiest months since 1929, when officials began to keep records, Haner said.
The heavy snowfall also has created dangerous instability and increased avalanche risks, Kramer said.
"It's been so deep and unconsolidated, it hasn't had time to stabilize," he said.
Strong winds, such as the kind that blew through last weekend, break down snow crystals and set up perfect avalanche conditions.
"It's kind of like putting bricks on top of potato chips," Kramer said. "Ideally you want the snow to be light and low-density on the surface and then gradually get firm as you go down. When the inverse happens, then you have unstable conditions."
On New Year's Day, high winds and warming temperatures created considerable avalanche dangers, he said.
That's when a 100-yard-long avalanche killed Shiela Rowe of Everett and Danny Woods, 63, of Custer, Whatcom County sheriff's Lt. Scott Rossmiller said.
Rowe and the others were riding snowmobiles north of Mount Baker. She was wearing an avalanche beacon, a device intended to help speed rescue. Her body was recovered Tuesday, Rossmiller said. Search-and-rescue teams found Woods on Wednesday after probing the snow with poles.
People venturing into the backcounty need to be prepared, Rossmiller said.
It's vital to take classes to learn how to assess the snowpack and carry the right equipment. People should travel in pairs and each person should carry a beacon, avalanche probes and a snow shovel, Kramer said.
"If you get caught in an avalanche, you're relying on your partner to rescue you," he said. "The old 911 on your cell phone isn't going to work in this environment."
Even powdery snow hardens like cement after an avalanche. The frictional forces melt the snow, which then quickly refreezes, Kramer said.
"Avalanche debris is like a rock. It's very, very hard," he said.
Most people buried in an avalanche die of asphyxiation within 30 minutes, Kramer said.
Finding places to enjoy the snow at lower elevations, in wind-protected areas and away from steep slopes reduces the risks, he said.
January continues to bring heavy snow in the mountains, Hamer said. Forecasters are predicting snow accumulation this weekend to be measured in feet rather than inches.
The snow, which is expected to be accompanied by high winds, will heighten risks, Kramer said.
In another fatal accident caused by snow, William Morgan, 67, of Everett died Monday when snow piled high collapsed his storage shed near his cabin in Mazama. Morgan was trapped beneath the snow and rubble.
The Associated Press contributed to this report.
|