BOISE, Idaho (AP) — Firefighters gained ground on a number of wildfires across the West but struggled in southern Idaho, where winds fanned a fast-moving blaze across 235 square miles of sagebrush and dry grass, threatening a handful of homes, authorities said Monday.

More firefighters were headed to the Idaho wildfire that was sparked by a Saturday lightning storm and had spread to 150,000 acres. The fire was threatening six homes in the Castleford area, west of Twin Falls, said Bureau of Land Management spokeswoman Kyli Gough.

Firefighters made progress in California, Utah, Wyoming Colorado and Montana, where the country's biggest wildfire is burning, according to the National Interagency Fire Center.