BILLINGS, Mont. — Rapidly expanding wildfires across a broad swath of southern Montana have caused injuries and burned homes, buildings, and vehicles, authorities said Thursday, as firefighters struggled to contain the flames amid hazardous conditions.

The toll of the of fires remained uncertain. But at least three evacuation orders were in place and well over 150 homes threatened by blazes that in some cases burned unchecked.

High temperatures and erratic winds were forecast. And with at least nine large fires burning in Montana, officials said there was increasing competition for adequate equipment and personnel.

‘‘Everybody’s competing for resources around here. We hope for everything but take what we can get,’’ said Karen Tuscano of the US Forest Service.

Tuscano was responding to a new wildfire in the Paradise Valley near Yellowstone National Park. The Pine Creek Fire that ignited Wednesday resulted in minor injuries to firefighters and members of the public, the Park County sheriff’s office said.

Wildfires were burning in at least six other western states, including a blaze in Wyoming’s Teton Wilderness that has scorched 19 square miles after making a big run Wednesday.