HEMET -- Investigators today are seeking the cause of an 81-acre wildfire in the unincorporated area of Sage.

The blaze broke out about 3:30 p.m. Monday near Sage Road and Minto Way in the area just southeast of Hemet, according to Jody Hagemann, a spokeswoman for the Riverside County Fire Department.

More than 130 firefighters, one helicopter and four air tankers contained the flames by 6 p.m. Monday, Hagemann said.

Firefighters remained on scene throughout the night and doused the fire by 8 a.m., she said.

Initially, several structures were threatened Monday afternoon as the flames crept up a slope at a moderate rate, but no evacuations were ordered, according to Hagemann.