Wildfires are still raging in seven states in the American West, including Washington, where dozens of Kiwi firefighters are currently helping out.
Understanding how wildfires burn not only helps combat them, but can keep firefighters safe.
"The fire is moving sometimes 1mi/h – well beyond the capabilities of ground crews to deal with," says fire behaviour analyst Dennis Burns.
He says millions of drought-stricken dead trees are burning fast, helping flames spread to healthy trees.
Carol Ewell leads the US Forest Service's Fire Behavior Assessment team. They're using flame-resistant camera equipment and sensors placed in the path of an 80,000-acre fire burning in California's Sequoia National Forest.
The technology helps them understand how to better fight the fires.
Last week alone, the US Forest Service spent nearly a quarter of US$1 billion fighting wildfires. It is now having to borrow from other programmes.
Watch the video for the full CBS News report.