A fire near the Grand Canyon National Park in Arizona has grown more than 20 times in size in 24 hours as an intensifying wildfire season sees the return of Canadian wildfire smoke into the U.S.

A park employee at the Grand Canyon was exposed to hantavirus, and a separate case of exposure to rabies in the park has also been confirmed.

Fast-spreading wildfires have forced the evacuation of part of the Grand Canyon, with the US National Park Service ordering visitors and residents away from its northern rim.

The NPS recommends avoiding hiking the Grand Canyon's inner trails between 10 a.m. and 4 p.m., when temperatures are at their peak. Temperatures in the inner canyon can reach over 120 degrees Fahrenheit in the shade, creating "extremely hazardous conditions for hikers," the NPS said.

A 42-year-old Utah man has died after he fell while descending a mountainside in Glacier National Park in northwestern Montana.