Streamflow forecasts through July are considerably below normal for Northwest Montana’s two main river drainages.

Numbers released by the U.S. Natural Resources Conservation Service on Thursday show the Flathead River’s expected flow during the next two months is 59 percent of normal with the Kootenai River forecast at 61 percent.

That’s a significant drop from last month, when the agency predicted the Flathead and Kootenai flows at 87 and 80 percent, respectively.

In a press release, water supply specialist Lukas Zukiewicz with the conservation service noted that much of that drop was the result of below-average snow accumulation last winter and snowpxack melting two to four weeks earlier than is typical.

“Some basins in the higher elevations of the state saw some late spring storms drop snow during [May], while the valleys received rain,” the release stated. “Unfortunately, the early transition of the snowpack in April to a melting and primed snowpack meant that melt began occurring shortly after these events occurred.”

In the Flathead Valley, total precipitation of .22 inches made last month the driest May on record.

The report lists current snow water equivalent — the amount of water still locked up as snow in the mountains. For the Flathead basin, the snow-water equivalent is 43 percent of normal while the Kootenai’s snowpack is 14 percent of average. However, those estimates only cover the portions of those drainages south of the U.S.-Canadian border.

Chuck Orwig, a hydrologist with the Northwest River Forecast Center, said Tuesday that while the U.S. portion of the Flathead River drainage is representative of the overall picture for remaining snowpack, most of the high-elevation snow still contributing to the Kootenai drainage is in higher-elevation areas north of the border. Still, he said he expects the overall snowpack is less than half of the norm for the Kootenai at this time of year.

According to data from the U.S. Geological Survey, the main stem of the Flathead River at Columbia Falls was flowing at 72 percent of normal on Friday morning. The conservation service press release added that “water users should be ready for below-average streamflows from snowmelt runoff this summer.”

Reporter Samuel Wilson can be reached at 758-4407 or by email at swilson@dailyinterlake.com.