Crews are using heavy machinery in several canyons in central Utah where landslides and storm runoff poured mud across roads and highways.
The Utah Highway Patrol said flooding late Thursday left several feet of mud on sections of U.S. 6 and that it remained closed Friday between Price and Spanish Fork.
The Highway Patrol said initial reports indicated several big rigs but no passenger cars were stuck in debris fields on that highway.
However, police said some people had to be evacuated from cars trapped on State Route 210 in Little Cottonwood Canyon.
There were no immediate reports of injuries.
The National Weather Service said there could be more flash flooding Friday, especially near wildfire burn scars and in slot canyons, normally dry washes and areas with poor drainage.