RENO, Nev. -- The massive wall of debris-laden water that roared down a Nevada valley Monday may be just the beginning of flooding and slides caused by the melting of a record winter snowpack in the Sierra Nevada.
Officials have been awaiting the coming of spring's warm temperatures with some anxiety a record 66 feet of snow fell near Donner Summit. In other places, snow depths reached 30 feet.
Some towns in the mountianous area remained a maze of white canyons in May. Houses two or three stories high were buried and invisible from the street, forcing owners to exit through wooden tunnels or narrow walkways shoveled through 25-foot drifts.
By the Memorial Day holiday weekend, melting snow began uncovering cars and trucks long abandoned to the relentless winter. With their roofs collapsed and windshields shattered, they protruded from snowbanks in mute testimony to the destructive power of the snow.
Weather experts say most of that snow will melt by late June. By then, mountain rivers will pour 13 million acre-feet more water into the state's flood-prone Central Valley, where soggy levees guard California's richest farmland and cities like Stockton and Sacramento.
A month ago, engineers in California at the state's Flood Control Center in Sacramento feared a spring hot spell might melt the snow so quickly that the California's network of dams and levees couldn't handle it.
'The peak period of the snow melt will be in early June,' said Flood Center spokesman Bill Helms.
Engineers at the state Department of Water Resources have said the big dams in the Sacramento River basin in the north end of the valley can contain the melted snow and protect California's Central Valley, the 540-mile-long centerpiece of the state's $14 billion agricultural industry.
About 250 miles southeast of San Francisco, storms and melting snow have flooded 94,690 acres in the usually dry bed of Tulare Lake, which dried up around the turn of the century when farmers took its water for irrigation.
Army engineers have thrown up dikes to keep the the revived lake from flooding the nearby towns of Corcoran and Stratford.
Highway 50, the artery linking the San Francisco area to the gambling center at South Lake Tahoe has been closed since April 9 by a landslide 50 miles east of Sacramento.
The mass of dirt, rocks and trees that roared down from a water-soaked mountainside covered 1,300 feet of the heavily traveled highway. It also dammed a fork of the American River and created an instant lake.
Engineers had to reroute the road around the lake. Rising river waters fed by the snow melt now threaten the new road, and it is being moved further from the river. A Memorial Day target for reopening Highway 50 was abandoned.
Steve Beucus, general manager of the Donner Public Utility District, estimated 50 percent of the homes in that area suffered some damage.
He said many summer residents are having a hard time clearing away enough snow to get into their homes.
It took several hours of work to get into his father's home, he said, pointing to a huge mound of snow next door.
'Only the top (of the third story) is uncovered and that's where you enter,' he said.