These boulders came down onto the Zion-Mount Carmel Highway in Zion National Park late Wednesday afternoon, forcing closure of a portion of the road/NPS

Monsoonal rains have brought flooding to Zion National Park in Utah and sent dumptruck-size boulders down on the Zion-Mount Carmel Highway, causing park officials to close a portion of the road between Canyon Junction and the East Entrance.

The rock fall occurred late Wednesday afternoon on the switchback near the Pine Creek Bridge and was blocking both sides of the road. A hazard geologist from the Utah Geological Survey was called in to help crews remove the rock and assess damage to the road. The road will reopen once it is deemed safe. The Scenic Drive and Zion Canyon remain open. The shuttle is running on a normal schedule.

Just before 1 p.m. Wednesday, the National Weather Service alerted Zion National Park officials that a strong thunderstorm was entering Zion, bringing with it intense rain and hail.

Heavy rains from a thunderstorm Wednesday caused flooding along the Virgin River in Zion National Park/NPS

Shortly after, the NWS issued a flash flood warning and Zion closed all of its slot canyons, including The Narrows where the Virgin River was flooding. Park officials said that at 2:10 p.m., "flooding on the switchbacks below the tunnel and in several other places forced the park to stop traffic at each entrance station and halt the shuttle system in place. By 4 p.m., park maintenance had cleared the Scenic Drive and the Mount Carmel Highway from the Scenic Drive to the South Entrance. The switchbacks had not yet been fully cleared of debris from the flash flood when the large boulder came down."

Alternate east and west routes are available via Highway 59 from Hurricane, Utah to Fredonia, Arizona, and Highway 14 from Cedar City, Utah, to Long Valley Junction and Highway 89. People traveling to the park may access the park by traveling east on State Route 9 from Interstate 15. All park facilities including the visitor center, museum, campgrounds, and shuttle buses are open and operating as normal.

Traffic advisory signs were to be placed near Mt. Carmel Junction, near Virgin, Utah, and near the park’s South Entrance. Road condition updates will be provided on the park website and social media outlets. The park’s short range radio broadcast systems at Mt. Carmel Junction, Hurricane, and both park entrances will also broadcast the status of the closure.