Rivers rage at record levels

Johnathan Hettinger -
Friday, June 8, 2018

Enterprise photo by Nate Howard

The Yellowstone River flows at 24,100 cubic feet per second this morning, according to the USGS. The average flow for this time of year is 13,900. The river is at 9.32 feet as of this morning. Flood stage is at 9.5 feet.

USDA NRCS Water Supply Specialist Lucas Zukiewicz is calling May “the Tsunami of 2018.”

The Yellowstone River, Boulder River, Shields River and Clark’s Fork river set new records for total monthly flows for May, as record snowpack melted.

“Snowpack peaked this year at well above normal to record-setting levels in the basin but made a quick transition to melt this water year,” Zukiewicz wrote in the June Montana Water Supply Outlook Report. “Almost like spring was skipped entirely, snowmelt began in earnest at low to mid-elevations during the latter half of April, and at all elevations by the beginning of May.”

Snowpack remains above average for most rivers in the Upper Yellowstone River Basin, with levels being 117 percent of normal basin-wide.

But Zukiewicz warned early runoff could mean water supply issues later in the summer.

“The promise of a record-setting snowpack delivering abundant water supply through the summer could easily turn into record-setting flows for a few months, and water shortages later in the summer when irrigation demand is high,” he said. “As always, it all comes down to the future weather. If rapid snowmelt persists, the need for summer precipitation will become increasingly important for those water users that are not along a reservoir controlled system.”

Precipitation levels were slightly below normal in the Upper Yellowstone River Basin in May.

“May and June are typically two of the ‘wettest’ months for basins east of the Divide, and although not the wettest months of the year in western basins, they still make up for a significant amount of moisture,” he said. “If the warm and dry pattern continues, this water will not make it into the rivers and streams as we venture further into summer, and could have significant impacts on the amount of water in rivers and streams.”