The Apple Fire burning in the San Bernardino Mountains north of Beaumont was sparked by a vehicle malfunction, authorities announced Monday.
Cal Fire investigators determined that a diesel-vehicle emitting burning carbon from the exhaust system malfunctioned, igniting the massive inferno Friday evening. That conclusion was drawn from multiple independent witnesses, as well as corroborating physical evidence, according to a statement from the Riverside County Fire Department.
The fire has scorched 26,450 acres – or roughly 41 square miles – as of about 6:30 a.m. Monday, according to an update from the InciWeb incident information website. The blaze grew by nearly 6,000 acres overnight.
Containment on the fire, which began in Riverside County and has spread to parts of San Bernardino County, stands at 5%.