LOS ANGELES, July 4 (Xinhua) -- An aggressive wild fire burning in America's western state of Utah Wednesday prompted new residential evacuations and closure of Highway 40.

The fire, dubbed "Dollar Ridge Fire", grew overnight from 30,000 acres (121.4 square km) to 40,469 acres (163.8 square km) with only about 1 percent containment, according to the U.S. Forest Service. The agency predicted the blaze will grow throughout Wednesday as it burns through dry timber, grasses and shrubs.

Under hot, dry and windy condition, Dollar Ridge Fire, the largest in the state's history, has destroyed 20 to 30 homes and structures since Monday night.

Since the flames shifted north after 5 p.m. on Wednesday (0000 GMT on Thursday) and were about 300 yards from Highway 40, new evacuation has been issued and the highway has been closed.

As all seven wildfires were burning in Utah on Wednesday and the National Weather Service issued the Red Flag warnings across much of the northern, western and central parts of the state, Utah Governor Gary Herbert also issued a state of emergency.

Local KUTV news channel reported that officials believed that human activity caused the fire.