Firefighters were working in extreme temperatures across the US west and struggling to contain wildfires, the largest burning in California and Oregon, as another heatwave baked the region, straining power grids.
The largest wildfire of the year in California — the Beckwourth Complex — was raging along the Nevada state line and has burned about 140 square miles as of Monday morning and state regulators asked consumers to voluntarily “conserve as much electricity as possible” to avoid any outages starting in the afternoon.
In Oregon, the Bootleg Fire exploded to 240 square miles as it raced through heavy timber in the Fremont-Winema National Forest, near the Klamath County town of Sprague River.
The fire disrupted service on three transmission lines providing up to 5,500 megawatts of electricity to neighbouring California.
A wildfire in south-east Washington grew to almost 60 square miles while in Idaho, Governor Brad Little has mobilised the National Guard to help fight fires sparked after lightning storms swept across the drought-stricken region.
The blazes come as the west is in the midst of a second extreme heatwave within just a few weeks and as the entire region is suffering from one of the worst droughts in recent history. Extreme heat warnings in California were finally expected to expire on Monday night.
On Sunday, firefighters working in temperatures that topped 100 degrees Fahrenheit (38C) were able to gain some ground on the Beckwourth Complex, increasing containment to 23%.
Late on Saturday, flames reached the US 395 road, which was closed near the small town of Doyle in California’s Lassen County.
The lanes reopened on Sunday, and officials urged motorists to use caution and keep moving along the key north-south route where flames were still active.
“Do not stop and take pictures,” said the fire’s operations section chief Jake Cagle. “You are going to impede our operations if you stop and look at what’s going on.”
Mr Cagle said structures had burned in Doyle, but he did not have an exact number.
Bob Prary, who manages the Buck-Inn Bar in the town of about 600 people, said he saw at least six houses destroyed after Saturday’s flare-up.
The fire was smouldering on Sunday in and around Doyle, but he feared some remote ranch properties were still in danger.
“It seems like the worst is over in town, but back on the mountainside the fire’s still going strong,” Mr Prary said.
A new fire broke out on Sunday afternoon in the Sierra Nevada south of Yosemite National Park and by evening covered more than six square miles, triggering evacuations in areas of two counties.
Containment was just 5% but the road leading to the southern entrance of the park remained open early on Monday.
In Arizona, a small plane crashed on Saturday during a survey of a wildfire in rural Mohave County, killing both crew members.
The Beech C-90 aircraft was helping perform reconnaissance over the lightning-caused Cedar Basin Fire, near the tiny community of Wikieup north-west of Phoenix.
Officials on Sunday identified the victims as Air Tactical Group Supervisor Jeff Piechura, 62, a retired Tucson-area fire chief who was working for the Coronado National Forest, and Matthew Miller, 48, a pilot with Falcon Executive Aviation contracted by the US Forest Service.
The National Transportation Safety Board is investigating the crash.
A wildfire in south-east Washington had burned almost 60 square miles as it blackened grass and timber while it moved into the Umatilla National Forest.