* Hundreds of residents evacuated in four western states
* Lightning sparks more than 100 blazes in Washington state
Wildfires burning across the northern Rockies threatened hundreds of homes on Monday in Idaho, Wyoming and Montana, while firefighters in Washington state scrambled to battle scores of blazes sparked by weekend lightning storms across the eastern Cascades.
No injuries were reported across the four western states on Monday. Hundreds of people have been displaced by fires in the region, and hundreds more were advised to be ready to flee at a moment's notice, including residents in the resort of Jackson, Wyoming, at the foot of the Grand Tetons.
The National Interagency Fire Center in Idaho reported nearly 30 large, uncontained wild-land blazes being fought nationwide on Monday, mostly in the West, in a destructive season that far surpasses the 10-year average for acreage burned in the year to date.
One of the most immediate threats to populated areas was a wind-stoked fire that has destroyed an unspecified number of dwellings and forced the evacuation on Sunday and Monday of 500 people near Casper, Wyoming.
The blaze on Casper Mountain south of the city had doubled in size to 10,000 acres (4,050 hectares) since erupting on Sunday from unknown causes and was being spread quickly by winds gusting to 60 miles an hour (96 kph), Casper Fire Department spokesman Bob Fawcett said.
About 250 miles (400 km) across the state to the west, a smaller fire suspected to be caused by humans raged near the popular tourist destination of Jackson Hole, prompting authorities to place at least 1,600 property owners on standby for possible evacuation.
That blaze, dubbed the Little Horsethief, erupted on Saturday and had raced by Monday across more than 2,000 acres (810 hectares) of the Bridger-Teton-National Forest, engulfing towering trees and torching sagebrush and grasslands.
SMOKE BILLOWS OVER WYOMING ARTS FESTIVAL
Emergency officials said the fire forced the closure of hiking trails and other operations in and around the Snow King Resort, a ski area with a conference center and luxury hotel perched above downtown Jackson.
Columns of smoke towered over Jackson, where an annual fall arts festival that draws artists and collectors from around the world was in full swing on Monday.
Farther northwest, a lightning-caused fire led authorities in Montana to issue evacuation notices for 400 homes and business on the outskirts of Hamilton, about 40 miles (64 km) south of Missoula in the Bitterroot National Forest.
The so-called Sawtooth Fire has consumed some 1,300 acres (530 hectares) of mountainous pine woodlands and grasses since it erupted on Aug. 30, fire information officer Chris Fox said.
The blaze outside Hamilton was burning about 50 miles (80 km) north of where a larger conflagration in Idaho has forced the evacuation of 400 other properties along a stretch of U.S. Highway 93, including the tiny towns of North Fork and Gibbonsville, along the border with western Montana.
The Mustang Complex Fire has devoured at least 280,000 acres (113,000 hectares) of pine forests since it grew from several separate lightning-sparked blazes in late July in remote stretches of the Salmon-Challis National Forest.
Although flames advanced to within a few miles of populated areas there on Monday, no structures were reported lost so far.
Fresh wildfire threats were not confined to the Rockies.
Thunderstorms that rolled through north-central Washington state starting on Saturday evening and continuing through Sunday afternoon unleashed at least 3,000 lightning strikes, triggering more than 100 fires across a four-county area on the eastern slopes of the Cascade Mountains.
The most menacing of those fires had scorched just 500 acres (200 hectares) by Monday, but prompted the evacuation of 180 homes in foothills west of the town of Wenatchee. A larger fire that has charred 6,500 acres (2,630 hectares) led authorities to order 20 homes evacuated near the nearby small town of Entiat.