More than 400,000 tons of mud, trees and debris plugged the North Fork of the Boise River with torrential slides in late August.
Culverts 18 inches wide grooved mountains. A stretch of the North Fork road now is the river channel. Prime trout streams are sluggish mud piles.
Much more is expected to wash out, scientists say.
Environmentalists blame the mess on too many roads and years of excessive timber harvests.
The Idaho Sportsmen’s Coalition filed suit Friday to stop the Boise River fire salvage sales, saying the cause also is controversial salvage logging.
If that’s true, it portends problems here. Some 180 million board feet of similar salvage logging is proposed on the Idaho Panhandle and Colville national forests.
U.S. Forest Service officials say the Boise slides are due to the 1994 wild fires that seared the soil and made it impermeable to rain. Coupled with sensitive watersheds and intense storms, the huge washouts were inevitable, the agency said.
Whatever the cause, scientists and environmentalists say national forests in North Idaho and Eastern Washington are on the brink of similar disasters. The Boise slides could be repeated on the portion of the Wenatchee National Forest, burned by the 1994 Tyee Creek fire, said Sam Mace of the Western Ancient Forest campaign.
Because people live in that sensitive watershed, “a blowout in that area could lead to a loss of life,” Mace said.
“The Colville (National Forest) better keep their guard up,” added Leon Neuenschwander, a professor of fire ecology at the University of Idaho. “This is not just an Idaho problem, this is a problem wherever ponderosa pine grows on steep slopes” and fires have been suppressed.
Even Mount Spokane State Park would be vulnerable to intense fire, followed by flooding and mudslides, he said.
Neuenschwander recommends thinning the smaller trees in dense stands, prescribed burning and reseeding native grasses to help hold the soil. Salvage logging - which can mean harvesting even the larger, more fire-resistant trees - doesn’t reduce the probability of Boise-style blowouts or help restore the forest. And roads exacerbate blowouts, he said.
“Close as many roads as you can, don’t build any more unless you absolutely need to and be real careful with those,” Neuenschwander warned.
Those points are key in a debate over what went wrong on a 184,000-acre portion of the Boise National Forest, east of Idaho City, where the Rabbit Creek fire burned last year.
It is home to 260 million board feet of proposed and ongoing salvage logging sales. All told, it is one of the largest salvage sales in the nation under new federal legislation that suspends environmental laws to allow more logging in burned areas.
In late August, a storm hammered the area, delivering 2 inches of moisture in a few hours. That sent sheets of water tearing across the ground and into streams.
Those streams grew as they poured down the mountains, gathering more trees, dirt, boulders and debris. Eventually, those wads plugged Bear River, Crooked River and the North Fork of the Boise River.
The damage rivals the historic logging road blowouts in the South Fork of the Salmon River in 1965, everyone agrees. That buried a significant portion of habitat for endangered summer chinook salmon and is a textbook example of how and where not to build logging roads.
Some environmentalists argue the logging and logging roads magnified the damage on the North Fork of the Boise. Where streams hit roads, they plugged the culverts with dirt and debris, they say.
That meant the rushing waters were dammed temporarily, building mass and momentum before blowing the road out and charging down the mountain, said Bill Haskins of the Ecology Center. He hiked to some of the most damaged watershed and found few areas where fire had sealed the soil.
Fires contributed to the problem, but “clearly these roads weren’t designed to handle this kind of event,” Haskins said.
Ron Mitchell of the Sportsmen’s Coalition found mudslides in several areas that hadn’t burned. Roads blew out in at least 30 places, including the Trapper Creek Road which “poured like soggy concrete down the hill,” he said.
Part of the blame rests on the Forest Service for not improving logging roads to take heavier storms, Mitchell said.
The Forest Service says it is reconstructing roads on the Boise to handle storms and insists salvage logging, past harvests and logging roads were inconsequential. Last summer’s Rabbit Creek fire was the sole cause, sealing the soil and preventing water from penetrating the soil, the agency said.
If anything, the roads slowed the torrents, reducing their force and lessening the damage, said Frank Carroll, Boise National Forest spokesman.
Some experts agree.
Walt Megahan, who directed soil and water research for the Department of Agriculture’s Intermountain Forest Research for 23 years, also flew over the North Fork. “There’s no way you can attribute the damage to the roads,” said Megahan, who now works for the National Council of the Paper Industry’s air and water quality arm.
UI’s Neuenschwander believes both sides are correct, but aren’t “seeing the whole picture together.” The area is fragile and once burned, such a rainstorm will cause mudslides, he said.
The one factor that makes it worse is “the number of roads in there,” Neuenschwander said.
People differ on what the final lesson is. The Forest Service says it means logging to reduce the probability of huge wildfires.
The Ecology Center’s Haskins says it shows the rush to salvage logging was a mistake. The Forest Service preached dousing every fire for 50 years, he said.
“Suddenly, there’s this emergency and we have to go into every forest and fix things,” Haskins said. “I’m not convinced that we’re smart enough to undertake this massive program without really mucking things up worse than ever.”
, DataTimes ILLUSTRATION: Map of area
MEMO: This sidebar appeared with the story: FUTURE SALVAGE SALES National forests in North Idaho and Eastern Washington will attempt to sell millions of board feet of “salvage” timber in the next two years. A million board feet of timber will build roughly 100 homes. According to U.S. Forest Service reports, sales include: 115 million feet in Panhandle National Forests. 105 million feet in Clearwater National Forest. 15 million feet in Nez Perce National Forest. 61 million feet in Colville National Forest. 158 million feet in Wenatchee National Forest.