Fire agencies report progress against dozens of wildfires burning across the western states of the US, while forecasters predict a gradual decrease in extreme temperatures.
Key points:

  • Fires have been raging across California, Oregon and Idaho
  • The heat wave is believed to have peaked, offering respite in the coming days
  • The biggest fire is in Oregon and currently burning across about 621 square kilometres

The fires have forced evacuations in numerous areas with scattered homes and tiny communities.
Some burned houses and other structures have been observed across the regions, but total losses are still being tallied.
The fires erupted as the western region of the US was in the grip of the second bout of dangerously high temperatures in just a few weeks.
A climate change-fuelled megadrought also is making conditions that lead to fire even more dangerous, scientists say.
California burns amid heatwave
Firefighters struggle to contain an exploding northern California fire under blazing temperatures as another heat wave hits the US west. 
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The US National Weather Service said, however, that the heat wave appeared to have peaked in many areas and excessive-heat warnings were largely expected to expire by Monday night or Tuesday.
The two largest fires were in forests in north-eastern California and southern Oregon, sending smoke across other states.
California burns against Nevada border
The Beckwourth Complex, two lightning-ignited blazes, covered about 362 square kilometres on Northern California’s border with Nevada.
Firefighters were contending with erratic winds, but temperatures were slightly lower.
The firefighting teams are hoping for some respite as the heatwave is tipped to peak on Monday or Tuesday.(AP: Noah Berger
Progress made in Oregon 
In Oregon, the Bootleg Fire covered 621 square kilometres.
After doubling in size at least twice over the weekend, it grew only incrementally on Sunday, a sign of some progress, said Rich Saalsaa, spokesman for the Oregon State Fire Marshal.
“It’s allowed firefighters to build more lines and go on the offensive,” Mr Saalsaa said.
Seven homes and 43 outbuildings have been destroyed in an area on the south end of the blaze, Mr Saalsaa said.
In central Oregon, a wildfire that started on Sunday doubled in size to 16 square kilometres.
Fires elsewhere 
Elsewhere, a forest fire started during lightning storms in south-east Washington state grew to 223 square kilometres.
It was 20 per cent contained on Monday.
In Idaho, Governor Brad Little mobilised the National Guard to help fight twin lightning-sparked fires that have together charred nearly 62 square kilometres of dry timber in the remote, drought-stricken region.
A new fire broke out on Sunday afternoon in the Sierra Nevada south of Yosemite National Park and by evening had exploded over more than 15.5 square kilometres, triggering evacuations.
The fire’s size, however, remained unchanged early on Monday and was 5 per cent contained. 
Homes are consumed by the Sugar fire, part of the Beckwourth Complex fire. (AP: Noah Berger
The July heatwave follows an unusual June siege of broiling temperatures in the West and comes amid worsening drought conditions throughout the region.
Global warming has contributed to the megadrought and is making plants more prone to burning.
Human-caused climate change and decades of fire suppression that increases fuel loads have aggravated fire conditions across the West, scientists say.