Yucca Valley firefighters responded to an arson fire in the desert east of Machris Park yesterday. About 7:17 p.m., a witness said a white man, dressed all in black, was seen running from a wash where a fire was burning about a 30-by-30-foot section of desert just west of Lisbon and La Contenta. Fire Captain Jay Dimoff said the fire had the potential to be a major fire if the wind had been right. Anyone with information should call the Sheriff’s Department at 760-366-4175.