Wind-whipped blazes roared through two states yesterday, charring about 38,000 acres and at least a half-dozen houses in Montana while destroying 14 structures and forcing the evacuation of scores of residents in Colorado. In Washington state, rivers surged over their banks and drove hundreds of people from their homes.

At least 10 rivers exceeded flood stage because between 6 and 9 inches of rain had fallen within 24 hours in the Cascade Mountains, causing runoff from the storm as well as from melting snow, the National Weather Service said. It predicted that some rivers will rise to twice flood level before the wet storm is replaced by cooler, drier air.

Every county west of the Cascade divide reported flood problems, although evacuations were required primarily from flood-plain farms and low-lying areas of scattered rural communities.

Gov. Booth Gardner (D) activated one unit of the Washington National Guard to assist in evacuations and sandbagging in the much-suffering flood plain north of Everett. Other units were placed on standby, and officials scrambled to find more sandbags after running out of them yesterday afternoon.

In Montana and Colorado, firefighters hoped for help from an arctic front bringing wind chill readings of 15 to 40 degrees below zero Fahrenheit.

The Montana fire, fanned by gusts of up to 100 mph, swept between the towns of Stanford and Hobson in central Montana, Jane Weber of the Lewis and Clark National Forest said.

Other fires burned hundreds of acres of prime grizzly bear habitat 200 miles to the northeast along the Rocky Mountain Front, 9,000 acres in northern Fergus County, and for a time threatened homes in the Great Falls area.

In Colorado, a fast-moving fire northwest of Boulder destroyed 14 homes and garages and forced the evacuation of scores of residents. Officials said a man identified as Arnold Stein, 62, was in custody on suspicion of arson. He is accused of setting his mattress on fire in his home, then pulling it outside, where the high winds spread the fire over 6,000 acres.

Officials believed they had the fire mostly under control, but at midday winds kicked up again, fanning the flames to 100-foot heights and forcing the evacuation of a subdivision.