At approximately 9 p.m. on Friday Aug 22, 2104, three large boulders and several smaller rocks rolled off the mountainside from the southbound or westbound side onto Sr-89/91 near mile post 5, between Mantua and Brigham.
These rocks came down from the north side of the canyon and landed on both north and southbound sides of the roadway. Two separate vehicles hit one of the larger boulders, causing both to rollover. Four other vehicles hit the smaller rocks and debris and sustained damage. Four people where transported to the Brigham hospital by ambulance with non-life threatning injuries.
The roadway was closed for 1-1/2 hours while the rocks, debris and vehicles were cleaned up from 9:30 p.m. until 11:05 p.m. UDOT responded and helped move the boulders and clear the roadway. One of the boulders was the size of a small passenger car. At 11:05 p.m. the roadway was opened back up to traffic.
At the time of opening the canyon it was still raining with the forecast for more heavy rain in Sardine Canyon so troopers will be monitoring the area for any signs of rocks or dangers in the area. The UDOT (Traffic Operations Center)TOC has the overhead signs on both sides of the canyon activated warning the motoring public of the possibility for rocks in the roadway.