High winds brought down trees across California Winter storm damage

Avalanche warnings were posted in the Sierra Nevada mountains after up to 5ft (1.5m) of snow fell. There were fresh flood warnings in southern California.

In Nevada, a levee burst after heavy rain, flooding hundreds of homes.

At least 440,000 people are without power from California to Oregon and Washington, roads have been closed and flights cancelled at some airports.

Weather forecasters said more rain and snow were predicted into early Monday, but that the weather system was weakening as it moved inland.

Trees uprooted

Two deaths have been reported so far as a result of the weather.

A woman was killed by a falling tree in Oregon. In Los Angeles another women died when her pickup truck was swept into a flood channel. Rescuers found her boyfriend clinging to a tree.

In Lyon County, Nevada, about 3,000 people were stranded after a levee, or dyke, along a canal broke early on Saturday, authorities said, and in parts of the town of Fernley water was up to 3ft deep.

In central and northern California, winds gusted up to 100mph (160km/h), overturning lorries and uprooting trees.

San Francisco was particularly badly hit, and a local state of emergency was declared, though there were no reports of casualties.

Flights in the San Francisco area have been grounded and storm winds meant large lorries were banned from the Golden Gate Bridge.

The former prison on Alcatraz Island in the bay was closed to tourists.

Warnings 'ignored'

Further south in California, areas denuded by October's forest fires were bracing for flooding and mudslides.

Some have enjoyed the wild weather brought by the storm

Emergency services have asked at least 3,000 people living in Orange County canyons to leave home as a precaution - though reportedly few have obeyed the instruction.

The Interstate 80 - the main east-west link between northern California and Nevada - has now reopened after snow in the Sierra Nevada forced its closure.

Although blizzard warnings have been downgraded, authorities are urging all non-essential travel be postponed.

In California, an emergency operations centre is co-ordinating the storm response, and Governor Arnold Schwarzenegger said he had spoken to the US Home Security Secretary, Michael Chertoff, by phone.