A fast-moving fire swept toward the mountain community of Idyllwild on Wednesday, burning 4,700 acres and five residential structures while threatening hundreds of homes.

The Cranston fire began about noon and spread rapidly, San Bernardino National Forest officials said. It has forced evacuations of more than 2,100 homes and is sending a massive tower of smoke rising over the San Jacinto Mountains. By 10:15 p.m. Wednesday, it was 5% contained.