Australian firefighters have arrived in the US to help battle out of control wildfires, which rage across five states.

Washington State was the worst affected, suffering the largest blaze in the state’s history. Fires also burned in California, Idaho, Colorado and Montana.

• Cars ablaze as wildfire engulfs freeway
• One dead in raging wildfires
• Hundreds evacuated in dangerous California blaze

Fire officials hoped calmer weather on Sunday would aid fire crews, but by Monday the fires burned through more than 1000 square kilometres and were expected to grow in the coming days, CBC News reported.

The California fires reached unprecedented levels, fuelled by dry vegetation as the state endures severe, multi-year drought conditions.

Some of the fires were so large they could be seen on satellite imaging, according to Mashable.

“The West overall has had its hottest year-to-date on record, and one of its driest such periods as well,” the article stated.