With spring in the air, hikers and climbers have begun heading for the hills. But some Snohomish County hills will be much harder or impossible to reach.

About six miles of the Mountain Loop Highway will remain closed this year, from Barlow Pass to the Bedal Campground on the Sauk River south of Darrington.

Heavy rains and massive flooding in October caused millions of dollars in estimated damage to "roads, trails, bridges, campgrounds, the whole ball of wax," said Ron DeHart, spokesman for the U.S. Forest Service’s Mount Baker-Snoqualmie National Forest.

"The enormity of the damage far exceeds our initial assessments," said Rob Iwamoto, acting U.S. Forest Service supervisor.

Recreation sites that had withstood previous 100-year flood events were damaged or wiped out, primarily on one weekend that brought more than 10 inches of rain in some places in a single day.

"This isn’t going to be repaired overnight. It’s going to take a couple or three seasons," DeHart said. "We’re trying to get a start on it now, and as the weather improves. It’s pretty awesome some of the areas that are blown away and inaccessible for spring hikers. They just won’t be able to get there."

The damage includes about 30 miles in Snohomish County of the popular Pacific Crest Trail "that’s just gone," DeHart said. Authorities are working with their counterparts in the Wenatchee National Forest on the east side of the Cascade Mountains to find alternate routes for hikers.

"We had other floods in ‘96 and ‘98," DeHart said. "It’s happened before, but not quite to this magnitude. This was the mother lode of storms we’ve seen in recent memory. This stuff came cascading down fast."

The first problem was just trying to get a handle on all the damage, since some areas are still covered with snow and authorities haven’t seen the full extent of the damage. The $12 million is just a preliminary estimate, he said.

The Forest Service has formed several assessment teams, which are learning more as the snow recedes and they can get into remote areas.

Some of the hardest hit are the Suiattle River drainage north and east of Darrington, and along the Whitechuck River, which drains into the Sauk River.

"There’s a number of fairly major recreation areas that are in need of some repair," DeHart said. "In some places, roads are impassable, bridges have been destroyed or removed. If we’re going to put everything back the way it was, it’s going to be a pretty monumental task."

In an aerial assessment last year, Forest Service personnel couldn’t even find Kennedy Hot Springs, he said.

At least 15 recreational trails and 20 trail bridges were damaged or destroyed, along with more than 40 roads or road segments that now are impassable. Out of 40 campgrounds in the National Forest, 13 in Snohomish, Skagit and Whatcom counties suffered damage, DeHart said.

The Kennedy Hot Springs ranger’s cabin and a nearby backcountry camp are buried under mud and debris, and some of the historical cabins at Monte Cristo were damaged or destroyed.

DeHart estimated the damage at $5 million for roads, $4 million for trails, $400,000 to $450,000 for campgrounds and other developed sites, and another $2.5 million for watershed and fish habitat losses on the Nooksack, Upper Skagit, Cascade, Stillaguamish, Suiattle and Whitechuck rivers.

Tackling flood-damaged areas poses a twofold problem: repairing the damage and finding the money to pay for it, he said.

Forest Service officials have applied for emergency relief funds for federal roads through the U.S. Department of Transportation, and expect to see some money from that source, he said.

DeHart urged people to check the agency’s Web site or the nearest ranger station before venturing into the forest and backcountry, especially those headed for higher-elevation recreational facilities. Many remain unsafe and will remain closed indefinitely.

Reporter Cathy Logg: 425-339-3437 or logg@heraldnet.com.

For more details on damage in the Mount Baker-Snoqualmie National Forest, visit the U.S. Forest Service Web site at www.fs.fed.us/r6/mbs.