A flood watch for 12 Montana counties, including Yellowstone County, will take effect Tuesday night and continue through Saturday morning, according to the National Weather Service in Billings.
"We are expecting the low elevations to see a considerable amount of rain, anywhere from 1 to 2 inches in the Billings area," said Dan Borsum, a senior forecaster with NWS Billings. "And we are concerned as the week progresses that the ground is already moist, this rain has nowhere to go. Coulees and ditches are going to start filling up, and rural roads are going to start getting soft."
The flood watch specifically cites the possibility for strong rises on creeks and streams, ponding water spreading to adjoining areas and rural, non-paved roads becoming impassable in places.
Counties listed in the flood watch include
- Big Horn.
- Golden Valley.
- Powder River.
Towns and cities within the flood watch include:
- Crow Agency.
- Lame Deer.
- Miles City.
- Red Lodge.
- Sheridan, Wyoming.
Of particular concern to NWS Billings is Big Horn County and other portions of southeast Montana where 2 to 3 inches of rain fell last week. The Little Bighorn River is one waterway that looks likely to run above flood stage, Borsum said.
"We're concerned as we he head into the week that some of the more important roads could see water impinging on them," Borsum said, of the flood potential near the Little Bighorn River.
Below average temperatures in the area will likely stave off flooding in the Yellowstone River by limiting snow melt. Billings typically sees temperatures in the 70s this time of year. Daily highs Tuesday through Thursday are expected to hit 45, 45 and 49 with lows of 39, 38, 39.
"Fortunately we're not seeing thunderstorms and snow melt at the same time, because those create the more dynamic situations," Borsum said.
Because flooding impacts are rainfall-dependent and have some variability, Borsum encouraged people to monitor weather updates throughout the week to see if flood impacts are expected in their areas. People in flood watch areas are also encouraged to monitor road condition information for potential travel impacts.