Montana news about the environment, natural resources, wildlife, climate change and more.

Thunderstorms across Montana bring potential for flooding

A Montana Department of Transportation map captured at 4:49 p.m. on May 30 shows widespread precipitation across Montana.

A series of slow moving and intense thunderstorms produced torrential rainfall and small hail in parts of central and southwest Montana Wednesday afternoon.

Flood advisories were in effect until 5:30 p.m. for Hill and Blaine counties. Thunderstorms with intense downpours, lighting and small hail pounded the Havre area Wednesday afternoon where up to over an inch of rain fell.

National Weather Service Missoula says upwards of a half inch of rain fell in just 20 minutes over Interstate 90 south of Deer Lodge Wednesday.

A flash flood watch is in effect through 6 p.m. Wednesday for the Butte/Blackfoot region.

Billings meteorologists have issued a flood watch from noon Thursday through Friday evening for parts of Rosebud County in southeast Montana. Slow moving local storms there could lead to excessive runoff and flash flooding.

Scattered showers are expected to persist through the weekend across most of the state.

Flood warnings, advisories and watches

Updated at 6 p.m.,  May 31, 2023
Western Montana

There is isolated flash flood potential until sunset through western Montana and north of Great Falls, according to the NWS Weather Prediction Center.

For the Butte/Blackfoot area, there is a flash flood watch in effect until 6 p.m., with slow-moving thunderstorms that are capable of producing heavy rainfall which may result in “rapid rises in small streams, or debris flows over area highways” according to National Weather Service Missoula.

Southwest Montana

Scattered thunderstorms are developing across the Billings area, with heavy rain, erratic winds and possible small hail through sunset.

Great Falls area

Thunderstorms with heavy rain, lightning, and small hail have continued in the Havre area, with officials advising residents to “be careful traveling, avoid flooded roads, and obey any road closures.” Flood warnings were in effect for Hill and Blaine counties until at least 5:30 p.m. this evening, where 0.5-1.5 inches of rain have fallen.

For the latest information on flooding, check the National Weather Service’s Missoula, Billings and Great Falls websites, along with the Montana Department of Transportation’s road map.

1. Flood warning - Take Action! A flood warning is issued when the hazardous weather event is imminent or already happening. A flood warning is issued when flooding is imminent or occurring.

2. Flood advisory - Be Aware. A flood advisory is issued when a specific weather event that is forecast to occur may become a nuisance. A flood advisory is issued when flooding is not expected to be bad enough to issue a warning. However, it may cause significant inconvenience, and if caution is not exercised, it could lead to situations that may threaten life and/or property.

3. Flood watch - Be Prepared: A flood watch is issued when conditions are favorable for a specific hazardous weather event to occur. A flood watch is issued when conditions are favorable for flooding. It does not mean flooding will occur, but it is possible.

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Edward O’Brien first landed at Montana Public Radio three decades ago as a news intern while attending the UM School of Journalism. He covers a wide range of stories from around the state.
edward.obrien@umt.edu.  
(406) 243-4065