As of Tuesday, snow levels were above average by as much as 56 percent in parts of central and western Colorado credited with supplying large amounts of water to the river system.

Elsewhere in the high country of Colorado, Utah and Arizona, the snowpack is almost double what it normally is this time of year with more winter storms in the forecast for this weekend.

The Las Vegas Valley gets about 90 percent of its drinking water from the Colorado, so more Rocky Mountain snow means a more secure supply.

Kay Brothers, deputy general manager of the Southern Nevada Water Authority, is somewhat optimistic about what she has seen so far.

"We're getting a whole lot of snow out there. That's good news," she said.

Brothers got an eyewitness account from the source of the valley's water recently when she talked to the man who looks after her cabin in the San Juan Mountains of southwestern Colorado.

"He couldn't find my house. It was just a bump in the snow," she said. "He had to shovel it off. He was afraid I was going to lose my roof."

Of course, a promising early snowpack easily can be wiped away by a hot, dry spring. Under the circumstances, some snow is lost to sublimation and dry mountain soil. Sublimation is the change from solid to gas, at no point becoming liquid.

That's what happened last year, when early predictions pointed to an average amount of runoff, but it never materialized because the snow stopped falling and mountains heated up. The same thing happened in 2006.

Pagano said many climate experts are predicting another warm and dry spring in the Rockies. But they also thought this winter would be a dry one, thanks to the Pacific Ocean weather generator known as La Niña.

"I don't think anybody saw this coming in terms of how wet it's been, but that doesn't mean they can't all of a sudden start being right," said Pagano, who works at the U.S. Department of Agriculture's Water and Climate Center in Portland, Ore.

Since 1999, there has only been one year when the Colorado River received above average runoff during the peak months of April through July.

Brothers said 2005, with its 111 percent of normal in-flow, was a welcome respite because "we didn't lose any ground that year."

In four of the last eight years, the river has received little more than half of its normal runoff. Inflow was 45 percent of average in 2004 and 30 percent of average in 2002, the river's driest year in a century.

What the Colorado really needs is a string of snow-rich years to help replenish Lake Powell and Lake Mead.

After eight years of sustained drought, the twin reservoirs are less than half full.

The seven states that share the Colorado River have agreed to let Lake Powell recover first before any extra water is released downstream to raise the level of Lake Mead.

As a result, Brothers said, the overall river system might improve, but it will take several more good years before Mead enjoys the benefits of above-average runoff in the river.

According to the latest projections by the U.S. Bureau of Reclamation, the surface of Lake Powell is expected to rise 25 to 30 vertical feet over the next two years. Over the same period, Lake Mead is expected to drop another 18 feet -- to its lowest level since 1965 -- before rebounding to a level roughly 7 feet below the reservoir's current elevation.

Those projections do not account for the heavy snow that fell in the Rockies in late January, but Roxanne Dey doesn't expect the bureau's forecast to change very much.

"It takes more than one good year to make up for several years of drought," she said.

Dey is spokeswoman for Lake Mead National Recreation Area, where staff members have been racing to keep up with the effects of falling water levels.

Over the past five years, the declining lake has forced two marinas to seek deeper water elsewhere on the reservoir.

A third marina is scheduled to move on Monday.

Dey said the 473 boat slips at Lake Mead Marina will be relocated to Hemenway Harbor, two miles away. There, they will become part of Las Vegas Boat Harbor marina, which was moved to its present location in 2002 from a spot that is now little more than a narrow stretch of Las Vegas Wash.

A part of Lake Mead Marina -- one dock with 288 slips -- was moved last year. A few weeks before that, Overton Beach Marina was divided into two pieces and sent to opposite ends of the reservoir.

Dey said the National Park Service plans to maintain a boat launch ramp in Boulder Harbor after Lake Mead Marina moves away. It and other launch ramps throughout the recreation area will be extended and improved starting this spring, when the water level usually bottoms out for the year.

Contact reporter Henry Brean at hbrean@reviewjournal.com or (702) 383-0350.