Firefighters were battling to quell the blaze near Hot Springs in Alabaugh, South Dakota, which also injured two firefighters and has incinerated about 3,000 acres (1,200 hectares), officials said.

Meanwhile, fire-related evacuations were underway in Utah and Idaho, while firefighters battled blazes in several states including Oregon, Arizona and New Mexico.

Weather officials have also issued warnings of fire risk for parts of Utah, western Colorado, and Southern California.

Hundreds of firefighters were needed to contain a massive forest fire in northern California's Lake Tahoe, a popular tourist spot 190 miles (300 kilometers) northeast of San Francisco.

Fire and forestry officials have said California is likely to see a severe fire season because of a dry winter marked by record low rainfall.

A handful of lightning fires continued to smolder in the two-million-acre (809,000 hectare) Inyo National Forest, where about 10 such blazes in recent days have charred "significant acreage" according to the National Weather Service.

The blaze caused officials to shut portions of Highway 395, the gateway to the Eastern Sierra Nevada mountains, but there have been no reports of injury or death.

Meanwhile, weather officials warned that a potentially deadly heatwave also was expected to settle over the eastern United States, with temperatures to soar this week to near 100 degrees Fahrenheit (38 degrees Celsius).

Heat advisories were issued Sunday and again Monday for a long swath of the east coast, with the National Weather Service warning that high humidity would create even more perilous conditions.