Reservoirs in the upper Snake River are holding more water going into this winter than at any other time in the past 10 years, good news for the water users who've dealt with a mostly dry decade.

Two of the system's three largest reservoirs were more than half full on Sunday, according to provisional data maintained by the U.S. Bureau of Reclamation. Water levels in American Falls and Palisades reservoirs were close to their average levels and each held nearly twice the water they did at this time last year. Jackson Lake - on par with last year's levels - held one and a half times its average amount.

The Upper Snake overall is 57 percent full. That doesn't set any records, but it is a significant improvement and a good omen for next year, said Mike Beus with Reclamation's Burley office.

"We're pleasantly full, and have enough carryover to have good stream flows through the winter," Beus said. "It's almost certain to refill storage next spring, even if we have severely deficient snowpack."

In fact, the main thing that Beus now thinks could derail a good year would be his agency misestimating its flood control measures in the spring. Full reservoirs and a reasonable snowpack can still lead to a year like 2007, he said, when water users asked for water before the snow finished melting, but after Reclamation had made room for the snowmelt in the reservoirs.

Forecasters already say the snowpack may not be great. A currently weak El Niño effect - basically, warmer water in the equatorial regions of the Pacific Ocean - is expected to strengthen and bring a warmer, drier winter to the Pacific Northwest, said Jay Breidenbach with the National Weather Service. That'll build on existing conditions: The U.S. National Oceanic and Atmospheric Administration announced last month that worldwide ocean temperatures hit a new record high this summer, based on records dating back to 1880.

All of the Magic Valley's canal companies and irrigation districts have shut down for the season, Beus said, though the North Side Canal Co. started up again to carry mitigation water for two groundwater districts.

American Falls Reservoir District No. 2 is also expected to carry out recharge work this fall. Neither is expected to draw enough from the system to substantially change the current outlook, Beus said.

"It's not causing us to change our operations," he said.

Of course, water in the Snake isn't going to help irrigators in other regions - including the Salmon Falls and Big Wood basins, lately victims of lingering drought effects. But Reclamation's recent data show the Little Wood Reservoir also holds more water than average right now and much more than it retained last year. The boost, Beus said, came thanks to June rains that kept demand low and left more water for later.

"June was really a boon to them," he said, noting that the Little and Big Wood rivers usually share similar conditions but do have different demands placed on them.