Small fire charges up Mission Valley hillside

A fire of unknown origin raced up a steep hillside between Interstate 8 and University Heights Thursday, blackening about four acres and forcing evacuations of homes and businesses but causing no reported structural damage.

The blaze began spreading off the 400 block of Camino del Rio South in Mission Valley shortly before 2:30 p.m. and spread rapidly up the steep slope to the south, according to the San Diego Fire-Rescue Department.

Police and emergency personnel cleared people out of a nearby hotel and several other commercial structures at the base of the hill and evacuated about 20 residences at the top, around Madison Avenue and Massachusetts Street.

Within 30 minutes, crews on the fire lines and aboard a water-dropping helicopter had largely stopped the spread of the flames, a dispatcher said. At 4:30 p.m., however, the burn area continued to smolder heavily and firefighters were continuing to spray down hot spots and flare-ups.

No injuries were reported. The cause of the blaze was under investigation.