The first major wildfire of the summer in the Morongo Valley in the US state of California raced across more than 5,500 acres (2,225 hectares) of tinder-dry desert brush, destroying at least six homes, threatening hundreds of others and sending residents of this sparsely populated desert community fleeing for their lives.
A second fire, about 35 miles (55 kilometres) away, burned across more than 2,000 acres (800 hectares) but did not threaten any structures, authorities said.
The larger blaze started when a single home went up in flames Wednesday afternoon and those flames quickly spread into nearby desert brush and tall field grass.
Elsewhere, fire crews fought back fast-moving flames approaching Arizona communities near a national forest. Two lightning-sparked brush fires blackened 12,500 acres (5,060 hectares), forcing the evacuation of 175 people from homes in the area. No injuries were reported.
By midnight only a few dozen homes remained under threat, with much of the fire having moved into a sparsely populated wilderness area.
Weather helped spread the fire rapidly, with sustained winds of about 10 mph (16 kph) and afternoon temperatures that topped 100 degrees (38 degrees Celsius) on the second day of summer.
More than 300 firefighters were said to be tackling the blaze, with more reinforcements being called in.