A wildfire that has scorched more than 47 square miles (30,080 acres) in northeastern Utah and killed three people has prompted the evacuation of hundreds of people from nearby towns and forced authorities to close a national forest to the public, according to AP. The fire started Friday morning north of Neola, about 100 miles (160 kilometers) east of Salt Lake City, and on Monday morning crews had it about 5 percent contained. The cause had not been determined. The fire began spreading into the Ashley National Forest Sunday afternoon, prompting federal authorities to close it to public use. The Federal Emergency Management Agency said about 300 people are under a mandatory evacuation. Another 150 homes could be threatened by Tuesday, said Derek Jensen, a FEMA spokesman. A U.S. Forest Service command team that travels the country fighting the largest fires joined local crews Sunday and took over direction of the firefighting efforts. Eleven-year-old Duane Houston escaped the fire but his father, 43-year-old Tracy Houston, and his grandfather, 63-year-old George Houston, were killed by the flames Friday as they worked in a hay field, authorities said. The owner of the field, 75-year-old Roger Roberson, died at a hospital, officials said Saturday. In Montana, residents of 40 to 50 summer homes just outside Yellowstone National Park were allowed to return home Sunday night as firefighters had a 6-square mile (3,840-acre) blaze about 60 percent contained. It began on Wednesday. Meanwhile in California, the state faced its first heat wave of the summer, increasing the fire danger in an already parched region. The wildfire that destroyed at least 254 homes south of Lake Tahoe was 100 percent contained Monday morning, fire officials said. A U.S. Forest Service investigation identified the cause of the fire that has displaced about 3,500 people as an illegal campfire. Authorities were gaining ground on a 482-acre (195-hectare) fire in the Los Padres National Forest northwest of Santa Barbara, which started Saturday and was 60 percent contained early Monday, according to a U.S. Forest Service fire information line. The blaze had closed some campgrounds, but no residents had been ordered to leave. A pair of wildfires also burned near the town of Julian about 60 miles (97 kilometers) east of San Diego. The larger of the two had consumed 110 acres (44.5 hectares) and was 20 percent contained by Sunday night, authorities said. The other blaze to the west blackened about 60 acres (24.3 hectares).