A fast-growing wildfire has exploded across 1,500 acres in Sonoma County and triggered evacuations for dozens of residents amid dry conditions and possible record-breaking heat Monday. The Sawmill fire, which is 20% contained, started at 10:50 a.m. Sunday off Big Geysers Road and Geysers Resort Road about 10 miles east of the picturesque city of Cloverdale, according to the California Department of Forestry and Fire Protection. Mandatory evacuations were issued for residents who live in the Geysers area. The firefight has been difficult for crews, fire officials said.