MILWAUKEE • An atmospheric river of moisture has swept parts of California and Nevada in the United States with another bout of heavy rains and snow, swelling streams to flood stage and piling up wind-blown snow drifts several metres high in the mountains.

The National Weather Service on Tuesday issued a blizzard warning for ski resort communities in the greater Lake Tahoe area, including the towns of Truckee and South Lake Tahoe, California, and neighbouring Nevada enclaves of Stateline and Incline Village.

Snow accumulations of 1.5m to 3m were forecast above elevations of 2,134m, with fierce wind gusts reaching 160kmh along the ridge of the Sierra Nevada mountain range, the Weather Service reported.

"This is a life-threatening situation," the weather agency said in a bulletin issued from its office in Reno, Nevada, urging all would-be travellers to stay indoors. "Even a short walk could be deadly if you become disoriented." The blizzard warning was set to remain in effect yesterday morning. An avalanche warning was issued for much of the same mountain regions.

Flood warnings were posted at lower elevations for 21 counties in northern and central California and a half-dozen counties in western Nevada, where creeks and rivers were expected to overrun their banks for a second straight day.

A series of floodgates on the Sacramento River, just upstream of California's capital, were opened for the first time in 11 years on Tuesday to divert high water around the city and into a special drainage channel, said Ms Lauren Hersh, a spokesman for the state Water Resources Department.

Heavy downpours on Sunday night and early Monday forced some 3,000 people to flee to higher ground in California's Russian River valley, while about 400 homes were evacuated in Reno as the Truckee River topped its banks.

REUTERS