Western Montana Is Starting To Thaw, Bringing Flood Potential

Mar 13, 2019

While a blizzard slammed parts of southeast Montana Wednesday, it seems winter weather is finally giving way to spring-like conditions west of the divide.

National Weather Service Missoula says spring runoff season is just about to start in earnest. 

“We’re going to start seeing some more and more runoff and we just want people to be aware that if there’s any place where water’s going to back-up or go into basements or not drain properly, this is a good time to move that snow around and make drainage areas,” says Meteorologist Jeff Kitzmiller.

Warmer temperatures are expected soon.

“We have 40s in for our highs for the whole weekend and next week. And we still see our (nighttime) temperatures back into the 20s. So it's a pretty good setup to not see a drastic melt off, but we are going to start seeing the snow get packed-down and get worked and get it to the point where it’s going to start releasing water."

The problem is the ground is still frozen across most, if not all of western Montana. Not only is there still plenty of snow on the ground, but that snow has lots of water content. For example, Kitzmiller says the snowpack in the Bitterroot Valley is holding four to five inches of water. The current threat is limited to places prone to lowland flooding:

“Not so much big rivers or anything like that, more like your roadways or dirt roads or places that get ponding of water.”

The weather service says now’s the time for people living in these areas to move personal items, equipment and livestock to higher ground and away from waterways. The agency also cautions that daytime snowmelt leads to black ice after dark. Road surfaces are likely to be slick each morning through at least early next week.

Kitzmiller says the average temperature in the Missoula-area from February first to March 12 of this year was 16.8 degrees; the coldest since 1893.

The water utility serving Missoula’s city residents cautioned customers to beware of frozen water lines. Cold temperatures have pushed the frost line deep enough to potentially freeze those service lines, which are buried 5 to 6 feet deep.

Those who have had it with winter will be happy to be reminded that spring officially starts next Wednesday.