WeatherWeather Wise


Weather Wise: Spring Streamflow

Weather Wise: Streamflow
Posted at 4:46 PM, Apr 10, 2023
and last updated 2023-04-11 10:38:15-04

HELENA — The warmest weather of the year so far has started the spring runoff. The water supply outlook is currently good across most of Montana heading into spring and summer, but there are some places that have not fared so well.

Right around April 10 is the typical peak of Montana's snowpack in the lower mountain elevations and the situation right now is promising. Overall most of the water basins in the state have had above-average precipitation so far this water year. Generally, Montana is in better shape farther south. The storm track this winter brought heavier precipitation across California, Nevada and Utah. Southern Montana was on the northern edge of this region with above-average precipitation.

Northwest Montana including the northern rocky mountain front was drier than normal and has lower than normal snowpack at this time, so streamflow forecasts in the Northern Kootenai and Northern Flathead river basins are between 70-90% of normal. The St. Mary forecast is closer to 90%, but the Milk River Basin recently had 250% of normal snowpack.

Streamflow forecasts have increased across most of the rest of Montana including the headwaters of the Missouri. The Beaverhead, Madison and Gallatin streamflows are likely between 120 to 180% of normal. West of the divide, streamflow forecasts at roughly 110-130% of normal.

Even with roughly average precipitation and temperature through April into May, Montana is generally in good shape right now.