SPARKS, Nev. - A wet winter Sierra storm triggered mudslides closing parts of major highways north and west of Lake Tahoe, and shut down dozens of roads in the Reno-Sparks area where flooding forced the evacuation Sunday of hundreds of homes, with more rain on the way.
"This is a serious flood situation," the National Weather Service said in a special flood statement late Sunday night. Flood warnings continue along much of the Sierra's eastern front and western Nevada into Tuesday.
More than 1,000 residents voluntarily evacuated one south Reno neighbourhood where drainage ditches started overflowing Sunday afternoon as the Truckee River approached its highest level in more than a decade, Washoe County emergency officers said.
Nearly 400 dwellings remained evacuated late Sunday night and hundreds of people were expected to be housed overnight in emergency shelters at two high schools — one in Reno and one in Sparks, county spokeswoman Nancy Leuenhagen said.
No injuries had been reported.
Rain, sometimes heavy, continued late Sunday night. Nearly 5 inches had fallen in the Galena Creek area southwest of Reno near the Mount Rose Highway and more than 4 inches in Lemmon Valley north of the city, the weather service.
Bob Elsen of Sparks said he saw plenty of wet weather in his former hometown of Bremerton, Washington, but he didn't expect it in Nevada's high desert where only 8 inches of precipitation falls annually on average.
"I don't think I've seen this much rain since I moved here six years ago," Elsen said as he watched the Truckee River's waters rise in Sparks. "It's why I moved out of Washington to get away from this stuff."
Reno police closed all bridges crossing the Truckee River in the downtown casino district, and two I-80 off-ramps in east Sparks were shut down. The worst trouble was expected during the Monday morning commute along the I-80 corridor between Reno and Sparks, where the Truckee River now is expected to crest about 6 feet above flood stage by 3 a.m.
A similar flood in the winter of 2005-06 sent about 5 feet of water into the Sparks industrial area, where more than 25,000 people work.
The University of Nevada, Reno and all area schools have cancelled classes Monday and Gov. Brian Sandoval is urging all non-essential state employees to stay home.
All westbound lanes of Interstate 80 near Donner Lake west of Truckee, California were closed indefinitely Sunday night because of a large mudslide. The westbound lanes of U.S. Highway 50 near Kyburz also were blocked.
Flooding closed U.S. Highway 395 from Lee Vining, California north to the Nevada line. An avalanche — and later a mudslide — also closed a portion of the Mount Rose Highway connecting Reno to Lake Tahoe for the second time in three days after more than 6 feet of snow fell atop the Sierra last week.
"All first responders are all hands on deck," Washoe County Emergency Manager Aaron Kenneston told reporters at a briefing in Reno Sunday.
Bob Leighton, the Reno Fire Department's chief of emergency operations, called it "a very dynamic situation that's happening so fast it's hard to keep up with the road closures."
The storm surge stretching all the way from Hawaii — called an atmospheric river — comes as California enters its sixth year of drought. Each drop of rain is welcomed, but officials said several more big storms are needed to replenish depleted groundwater supplies.
Relatively mild temperatures were driving up the snowline to above 9,000 feet throughout the Sierra Nevada, causing runoff in the lower elevations, where the ground is already saturated. Forecasters said Sunday it was tracking pretty much as they expected.
"For forecasters who've been here a decade or more, this is one of the most impressive atmospheric setups that we have seen in a long time for potential flooding in the region," said Chris Smallcomb, a weather service meteorologist in Reno. "If you had to write a textbook on how to get a flood in the region, you would use a scenario just like this."