 Wildfires are sweeping across parts of Utah and other western states |
One person has died and 27 homes have been destroyed in South Dakota's Black Hills, local officials said.
Residents of at least 50 properties had already fled the fire, which has burned across nine sq miles (23sq km) after it was sparked by lightning on Saturday.
Temperatures as high as 38C (100F) have followed a drier-than-normal winter, creating ideal conditions for fires.
"This thing blew up because of extreme hot temperatures and the winds," Joe Lowe, South Dakota state wildland fire co-ordinator told the Associated Press news agency.
"It came out of the canyon with a vengeance," he said.
California, Colorado, Arizona, Idaho, Montana, Nevada, New Mexico, Washington state and Oregon have also been affected by fires, forcing many people to evacuate their homes.
Lightning strikes
In Utah, the largest wildfire in state history has destroyed almost 300,000 acres (120,000 hectares).
Several road accidents have occurred on a stretch of highway near Richfield, Utah, including one in which two people were killed. Highway patrols blamed poor visibility from smoke.
More than 34,000 acres (13,800 hectares) have been scorched in California's Inyo National Forest and campgrounds had to be evacuated.
"Everything is very, very dry," said Nancy Upham, a spokeswoman for the Inyo National Forest.
 The high summer temperatures follow an unusually mild winter |
In the Los Padres National Forest in southern California 11 firefighters were injured as they battled to save 22 homes.
Residents were evacuated from nearly 300 properties over the weekend near Wenatchee, Washington, where high winds have fanned fires.
In Nevada, some 1,500 evacuees were allowed home after a fire at an electrical substation shut down the inter-state highway and caused major disruptions to train services.
Many of the fires have been blamed on lightning strikes in tinder-dry forest areas, after a mild winter which saw lower-than-average rainfalls.
