Late-December snowstorms have brought most Idaho snowpacks close to where they need to be this time of year. But some areas of the state could still face slightly below-normal irrigation supplies this year, concludes the first monthly water-supply analysis of 2009.

The report, issued by the U.S. Department of Agriculture's Natural Resources Conservation Service, matches statements made last week by Ron Abramovich, a water supply specialist with the federal agency. The monthly report is published between January and June each year to help farmers, cities and others who rely on Idaho rivers predict what they'll have to work with.

The good news for the Magic Valley is that southern Idaho has the edge this year. As of Jan. 1, most of the state's basins hold at least 90 percent of their average snowpack levels - slightly higher in the south, and lower up north where overwhelming snowfall has largely ended up in valley areas.

December's snowstorms weren't quite enough to make up the milder weather of the two previous months, according to the report. But forecasts suggest irrigators should expect between 70 and 97 percent of average stream flows.

Depending on their location, they'll get a little extra help from the region's reservoirs. Those in the upper Snake area continue to be close to or above average. But south-central Idaho hasn't fared nearly as well: The report cites Magic and Salmon Falls at roughly 30 percent of their average capacity for the date, Oakley at 62 percent and Little Wood at 57 percent.

NRCS scientists will speak to the Salmon Falls basin at the Salmon River Canal Company's annual shareholder's meeting, 1 p.m. Monday at the Hollister Elementary School Gym.

The report's authors noted the avalanches and avalanche risk the heavy snows have produced, and encouraged skiers, snowshoers and anyone else planning to visit the mountains to take a basic avalanche class - even if they're just going to a ski resort. Idaho continues to be in the path of future storms, the report states.

The report comes as scientists are preparing for their first meeting of the year to evaluate Idaho's water supply outlook. The Idaho Water Supply Committee, made up of water managers and hydrology experts from state and federal agencies and the private sector, will gather Thursday in Boise to discuss weather, climate, reservoir operation, river flows and snowpack. The meeting is open to the public and starts at 10 a.m. on the sixth floor of the Idaho Water Center building.

Nate Poppino may be reached at 208-735-3237 or npoppino@magicvalley.com.

• Snake River at Heise: 90 percent of average • Camas Creek near Blaine: 65 percent • Little Lost River near Howe and Big Wood River: 69 to 81 percent • Big Lost and Little Wood rivers: 85 to 88 percent • Oakley Reservoir Inflow: 85 percent • Owyhee River below Owyhee Dam: 88 percent • Salmon Falls Creek near San Jacinto, Bruneau River near Hot Springs: 95 percent The Surface Water Supply Index, which combines reservoir information with stream flow forecasts, shows a potential for irrigation shortages in several basins, including Big Wood, Oakley and Salmon Falls. NRCS water reports can be found at http://www.id.nrcs.usda.gov/snow/watersupply/