Wednesday, January 9, 2008

Robust storm wreaks havoc

Numerous avalanches slide in Warm Springs Creek drainage, elsewhere

Express Staff Writer

Ketchum resident Nancy Ferries knew something was amiss when she heard a loud commotion outside her lower Warm Springs house around 2 p.m. Saturday.

"All of a sudden I heard a kind of 'whoosh,'" Ferries said by phone Tuesday.

At first, she said, she couldn't determine the source of the sound due to her being inside her and husband Chuck Ferries' home. Her only indication was the blur of white she saw pass by a nearby window out of the corner of her eye.

But as things turned out, being inside the solidly built house was a fortunate if not entirely planned circumstance.

Peering outside, Ferries quickly spotted the source of the disturbance. Covering the upper deck of their home, piled up on top of the small, two-car garage adjacent to the house and spilling all the way onto Huffman Drive in front, were the tumbled remains of a large avalanche that had swept over the top of the house.

Located at the base of a large avalanche path that runs nearly 1,000 feet down from a pronounced saddle on Warm Springs Ridge, the fast-moving torrent of snow also tore out decking and panels on the home's upper deck.

Knowing that the prominent gully above the home slides during the winter from time to time, a sturdy avalanche-proof wall was added to the design of the hillside home. And at least this time, the wall appears to have worked.

Not even a crack has appeared on the walls inside the house, Ferries said. She said a subsequent inspection by a building inspector also revealed zero damage.

"It was totally fine," she said. "This house is unbelievable."

But for the garage nearby, things didn't turn out quite so well. Pouring over the top of the 40-year-old structure, the weight of the snow caved in a portion of its angled roof.

Fortunately, the one car that in the garage at the time of the slide wasn't damaged, and the couple is already thinking of remodeling the structure later this year, Nancy Ferries said.

"We were going to do it in the spring (anyway)," she said.

The avalanche was caused by a massive, moisture-laden Pacific storm that swept into Central Idaho from the southwest.

Measured at various locations throughout the Wood River Valley, snow depths ranged between 15 inches in valley-floor locations to nearly 3 feet in the uppermost alpine areas.

Coming into contact with a weak, older snowpack at nearly all elevations in the region, the new snow created a dangerous situation that convinced officials with the Sawtooth National Avalanche Center to implement a backcountry avalanche warning over the weekend. The warning, which officials lifted early Monday morning, advised people to stay off most out-of-bounds slopes until the danger subsided.

Still, even though they have lifted the widespread warning, avalanche officials continue to warn of significant avalanche danger in many areas locally.

"This sketchy snowpack is going to take time to stabilize, and for now it is best to stay off of and out from under steep slopes, even at valley floor elevations," avalanche center forecaster Chris Lundy said in his Monday morning avalanche advisory.

Lundy said the 2 feet of new snow and strong winds over the weekend overloaded a weak, faceted snowpack, causing widespread unstable conditions. The avalanche danger was heightened by gale-force winds that swept over the region.

All of those factors led to the widespread avalanche activity seen from Saturday on.

"There have been numerous natural and human-triggered slides and too many close calls," Lundy said.

Witnessing the high level of avalanche activity on Sunday was Idaho Mountain Express photographer Willy Cook. Driving out Warm Springs Road, Cook came to within 1.5 miles of the outlying Frenchman's Bend residential area before a large mound of avalanche debris stopped his progress.

Along the way, Cook witnessed the evidence of "hundreds" of slides on both side of the Warm Springs Creek drainage, he said later Monday morning.

In the Frenchman's Bend area, a number of homeowners were kept from leaving their homes for more than three days by a major avalanche that tore off of the north-facing slopes above Warm Springs Creek and covered the only road out for a significant stretch. Like much of the rest of the drainage, the slope had burned during last summer's 48,520-acre Castle Rock Fire.

Two of the Frenchman's Bend homeowners kept from leaving were Lisa Vierling and her husband, Michael Stoneback.

Vierling said she got a call from one of her neighbors, Earl Englemann, early on Saturday. Around 5 a.m., Englemann heard a loud noise coming from just beyond the 11 or 12 homes at Frenchman's Bend. On the road, he saw the avalanche debris that had slid off the nearby north-facing slope, Vierling said.

"Sure enough, it had pulled down," she said.

After the slide, calls went out to every home in the Frenchman's Bend area to see if all were safe and accounted for, Vierling said.

"We're all here," she said Monday afternoon, still trapped by the avalanche.

But being trapped at home hasn't been all bad, Vierling said.

"It's really kind of fun. It's a nice neighborhood," she said. "You feel like you're trapped in a snow globe."

Late on Tuesday, Vierling's husband, Michael Stoneback, reported by phone that Blaine County Road and Bridge crews had gotten through the slide, though no snowplow had passed by their home yet.

Closer in, between Vierling's home and the Ketchum city limits, another avalanche dammed up the waters of Warm Springs Creek for a period of time, Blaine County disaster services coordinator Chuck Turner told the County Commission on Tuesday. However, Turner said, the slide debris was no longer blocking the creek.

"It ate its way through," he said.

With the vegetation that typically holds snow in place in the Warm Springs Creek drainage and surrounding mountains burned off during last summer's major wildfire, Turner predicted that the area may not have seen the last of its avalanche troubles.

"It could be a tense moment or two out there this year," he said.

On the upside, the significant snowfall the region has witnessed since late last week has brought local snowpacks to just above average. According to the Natural Resources Conservation Service, the Big Wood Basin, which includes the drainages of the Big Wood River and Camas Creek, stood at 104 percent of average Tuesday.

The National Weather Service is calling for a chance of additional snowfall throughout the remainder of this week.

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