RIVERDALE (AP) - The mountain snowpack is off to a promising start in the Upper Missouri River Basin, but it will take a lot more, officials say.

With Lake Sakakawea more than 25 feet below the long-term norm, even a year of "average" runoff is not enough.

"In a perfect world, we'd like to see it rise 10 feet a year for a while," said North Dakota Game and Fish Department biologist Dave Fryda. "Usually it is epic events that drives the system. That's the nature of the Plains climate. We don't have averages."

Lake Sakakawea is expected to finish out this month at 1809.5 feet, and then drop to 1808 feet by the end of February. The 1808 mark is the elevation at which many of the boat ramps on the lake will no longer be in service.

The most used permanent boat ramps on Lake Sakakawea a year ago were at Fort Stevenson State Park, where the ramp is at 1,790 feet, and Lake Sakakawea State Park, at 1,800 feet. Other popular areas of the lake began the 2007 boating season with temporary ramps. Record spring rain in the lower reaches of the Missouri last year led to lower releases from Sakakawea and an unexpected rise in the lake.

"We also had about 8 inches of rain here in May and another 5 in June," said Dick Messerly, Fort Stevenson State Park manager. "That saved our bacon last year, no doubt."

The Army Corps of Engineers says the continued drought in the Missouri River Basin has taxed the storage system of the reservoirs.

Recent releases have been running much below the long-term norm, reducing the hydropower production that remains one of the chief reservoir functions.

March and April are critical months for moisture. The mountain snowpack normally reaches its peak about April 15.

Forecasters expect drought conditions to persist or intensify over eastern Montana and western North Dakota through March, with some improvement in western Montana.

"It's a crapshoot right now. There's no moisture in the soil. What can we do?" said Messerly about the early outlook. "Who would have guessed the drought would last this long."