A fire broke out on a semi-trailer rig Thursday morning, closing down U.S. 6 through Spanish Fork Canyon. Utah Highway Patrol gt. Todd Royce said the driver â who was unhurt â was able to detach the semi cab from its trailer, but flames completely destroyed the big rigâs load of paper products. As of 7:30 a.m., about three hours after the semi caught fire, one lane of the highway had been reopened at the scene.