Warm weather could cause area rivers to reach flood stage this week, due in part to a deep mountain snowpack. The National Weather Service in Missoula issued a hydrologic outlook on May 12 for much of western Montana in advance of the rising temperatures.
According to NWS-Missoula meteorologist Trent Smith, the snowpack in the Flathead Basin is 148 percent of normal for this time of year and if it melts rapidly that could cause problems for communities downstream. The snowpack is even larger in other areas.
“There is still plenty of moisture in the mountains and so those small rivers and streams will be running high this week,” Smith said.
The last time the Flathead region was threatened with flooding was in the summer of 2011. This year is also the 50th anniversary of the 1964 flood that ravaged much of the Flathead Valley and put Evergreen and parts of Kalispell underwater.
Temperatures will steadily increase throughout the week and are expected to reach the 70s and 80s by May 15. The Stillwater River at Lawrence Park in Kalispell is forecast to hit 7.14 feet by May 17, just a few inches short of the 7.5-foot flood stage. The area’s main rivers will also see slight increases, but nothing close to flood stage. The Middle Fork of the Flathead River near West Glacier was flowing at 4.6 feet on May 12 and was expected to hit 6.6 feet by the weekend. Flood stage on that river is 10 feet.
Further west in Lincoln County, the Yaak will be the river to watch. It is expected to hit 7.72 feet on May 17 near Troy; flood stage is 8 feet.
“Residents should keep an eye on the rivers; they won’t hit flood stage yet but they will be high and moving fast so people should be careful around the water,” Smith said.
While the heavy snowpack has elevated concerns about the potential for flooding, it’s good news for farmers and those concerned about wildfires. The National Interagency Fire Center is predicting that 2014’s fire season could arrive later than normal, particularly in northern Wyoming.
The lingering snowpack is keeping trees and other fuels at higher elevations wet, and that’s expected to remain the case in most areas until August, the Boise-based agency said in its most recent monthly outlook.
But confidence in a less-active fire season begins to fade beyond mid-August, meaning there’s potential for blazes to become more severe as the summer wears on.
For the latest information about flooding conditions across Northwest Montana, visit www.noaa.gov/a>.