LAS VEGAS — Tourists and truckers were told Wednesday to prepare for several more days of disruptive detours around a closed stretch of busy Interstate 15 in southern Nevada that crumbled in chunks during intense flash flooding.
Crews were working to repair the freeway as Gov. Brian Sandoval declared a state of emergency late Tuesday and dispatched officials to begin estimating the cost of damage after Monday’s storm wiped out swaths of the vital interstate and swamped parts of Clark County and an Indian reservation.
“We hope to have one lane in each direction open by the weekend,” Nevada Department of Transportation spokeswoman Julie Duewel said.
The National Weather Service said more than 4 inches of rain fell in less than two hours in the area during what might have been most intense storm in 30 years in the Muddy River valley and rural Moapa area about 50 miles northeast of Las Vegas.
The sudden torrent of runoff down sunbaked washes toward the Virgin River and Lake Mead also scoured out part of a main Union Pacific rail freight line and swelled a river so high that a Utah national park was briefly shuttered.
The same storm, spawned by seasonal monsoon moisture and the remnants of Tropical Storm Norbert, dumped heavy rain throughout the Southwest and set a single-day rainfall record Monday in Phoenix.
Convenience store manager Penny Hyde spent a harried day Tuesday in the I-15 exit town of Glendale, Nevada, advising motorists who waited through hours of delays and detours that to get back to the interstate they’d need to take another roundabout route on two-lane highways to Panaca, Nevada, and then to Cedar City, Utah.
“It’ll be a couple of hours out of their way,” said Hyde, who noted the remnant red mud all around her store.
No damage estimate was immediately available, but Clark County spokeswoman Stacey Welling said officials were preparing to ask county lawmakers next Tuesday for an emergency declaration.
During the height of the storm, about 190 people were evacuated from the Moapa Band of Paiutes reservation after tribal officials warned that waters were close to breaching a Muddy River dam.
But in a “near miss,” the water stopped short of spilling over, said Erin Neff, spokeswoman for the Clark County Regional Flood Control District.
A subdivision with about 30 homes flooded several miles downstream, in Overton, and Clark County firefighters counted 18 rescues in the area, many involving submerged cars.
Transportation officials said the damaged stretch of I-15 near Moapa could take weeks to be fully repaired. Duewell said it usually carries about 20,000 vehicles a day.
Union Pacific Railroad service was suspended while crews repaired track that was undermined and washed out near Moapa. Officials hoped to have the track bed and rails repaired by Wednesday for freight service to resume on the busy Las Vegas-to-Salt Lake City main line, railroad spokesman Aaron Hunt said.
In southern Utah, rangers at Zion National Park turned away visitors for several hours Tuesday when heavy rain and a surging river made park routes impassable. Mud, debris and a boulder blocked Route 9, the road through the main canyon.
A shelter remained open Tuesday night at a school in Overton, but Southern Nevada Red Cross chapter spokesman Lloyd Ziel said no residents used it.
More than 50 Red Cross and cooperating volunteers were going door-to-door in Moapa, Logandale and Overton to assess damage and offer help to residents, Ziel said Wednesday.
“Some people didn’t get touched, and some have several feet of water in their homes,” he said.