What looked like a normal year on the Colorado River took "a hard right turn" in January, as a sudden dry spell took hold in the mountains of eastern Utah and western Colorado, a federal water supply forecaster said Friday.

The disappointing snowfall totals prompted an ugly revision to the projections for how much water will flow into the Colorado later this year.

On Jan. 1, the forecast called for the river to receive about 91 percent of its average flow. Now the forecast calls for 74 percent.

"That's what you get for a dry month," said Tom Pagano, water supply forecaster for the U.S. Department of Agriculture's Water and Climate Center in Portland, Ore. "It was just a real big turnaround."

The Las Vegas Valley gets about 90 percent of its drinking water from the Colorado.

Seven years of record drought have left the river's two main reservoirs, Lake Mead and Lake Powell, at about 57 percent of their combined capacity. Several straight years of above-average snowfall and water runoff in the Rockies are needed to refill the reservoirs.

"Obviously, no, that isn't good news," said Scott Huntley, spokesman for the Southern Nevada Water Authority. "It's still a bit early to predict how the year will turn out. But obviously, you want the winter to get off to a good start, and this isn't that."

The bad news seems particularly surprising after a month filled with news accounts of winter storms in Denver. But Pagano said the recent storm activity has been limited to the eastern side of the Rocky Mountains, while the Colorado River gets its water from snow that falls on the western side.

"You can pretty much draw a line down the Continental Divide of where the good snowpack is and where the bad snowpack is," he said.

A snowy February could go a long way toward reversing the current trend, Pagano said. "Is it going to be a blockbuster month? We'll have to wait and see."

Such volatility is nothing new for the Colorado River. Over the course of a single month last spring, an unexpected dry snap sent snowpack estimates tumbling. Until then, the basin seemed poised to enjoy one of its wettest years since drought descended on the basin in the late 1990s.

During the past eight years, the Colorado River has received just 55 percent of its average flow of water.

Pagano said it's not too late for this year's snowpack totals to rebound, but the situation is bad enough in parts of Utah that forecasters now rank the chances of getting back to normal as "slim and none."

"This is why it's so very important that we diversify our water portfolio from reliance predominantly on the Colorado River," Huntley said. "It's also why we need the community's continued support for water conservation and following the watering restrictions."