Arizona’s senators are demanding answers from the Department of the Interior over its handling of a devastating wildfire that is still burning out of control on the Grand Canyon’s North Rim.

U.S. land managers are racing the clock as hotter, drier weather raises the risk of wildfires in the nation’s overgrown forests with each passing year.

Arizona Governor Katie Hobbs has demanded an independent investigation into why National Park Service staff let the fire burn during the driest time of the summer in a botched attempt to reduce wildf...