RENO — As the first wet storm of the spring sweeps into the mountains around Lake Tahoe, wary water managers are watching the sky and already releasing water from swollen reservoirs to guard against flooding across northern Nevada.
After a winter that saw more than double the normal snowfall in some parts of the Sierra and nearly three times what the region received last year, the people who control water releases say the threat of flooding could extend into July.
“There is so much water in abundance this season, there’s nothing we can do with it all,” said Rusty Jardine, district manager for the Truckee Carson Irrigation District that depends on the snowmelt to provide water to 2,500 farmers and ranchers in the high desert east of Reno.
Four to 8 inches of snow was possible Tuesday into Wednesday on the highest Sierra passes, including the Mount Rose Highway southwest of Reno and Donner Pass on Interstate 80, west of Truckee, California, the National Weather Service said. Isolated showers were expected across much of northern Nevada, with another round of mountain snow and valley rain Friday and Saturday.
Last week’s unusually warm weather helped accelerate snowmelt above Tahoe, where the Mt. Rose Ski Resort already has recorded a season-record 56 feet of snow.
Seasonal peak river flows usually not seen until May already are moving through the Truckee, Carson and Humboldt rivers.
Lake Tahoe started spilling water on Feb. 23, the earliest since 2006. Current forecasts call for it to reach capacity near the end of July, federal water master Chad Blanchard said.
“We don’t want to fill it too early and have to pass a lot of water,” he said Tuesday. “We are trying to get ahead of it and make some releases ahead of time and try to get out the volume of water in the snowpack that we don’t have room for.”
Last week, when a California highway crew found an abandoned Jeep Cherokee buried beneath 20 feet of snow near Truckee, the Truckee Carson Irrigation District already had been working for a month on a strategy to maximize use of the precious precipitation while minimizing flood threats around Fallon 60 miles east of Reno.
“We’re not going to be able to place it all to a beneficial use so obviously we have to make sure not to create any damage,” Jardine said Tuesday.
It’s a far cry from just two years ago when users of the district’s water users received only 21 percent of their normal supply — the worst on record since the Lahontan Reservoir was built in 1915. It can hold about 300,000 acre-feet of water, but the Sierra snowmelt is expected to send as much as 525,000 acre feet into the rivers feeding the reservoir this spring.
Last month, crews cleaned debris from the Carson River to improve flows and built a new diversion to help steer water out into the uninhabited desert. State and county transportation workers also constructed a new culvert to send water through tunnels beneath U.S. Highway 95 near Fallon.