Flood in Montana, June 9, 2023

Name: Flood in Montana, June 9, 2023
Start: 2023-06-09T11:13
End: 2023-06-09T21:24
Location: Montana

June 9, 2023 · NWS GGW · 1 event in 1 county or zone

Heavy rainfall caused the Musselshell River to rise above flood stage for a few hours.

Where it happened

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The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 1

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS GGW wrote it up.

Heavy rainfall caused the Musselshell River to rise above flood stage for a few hours.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Glasgow, MT wrote its last area forecast discussion before the first event at Jun 9, 1:23 AM MST, 9 hours 50 minutes earlier.

Area forecast discussion, Jun 9, 1:23 AM MST, 9 hours 50 minutes before

Area Forecast Discussion
National Weather Service Glasgow MT
223 AM MDT Fri Jun 9 2023

.DISCUSSION...

A quasi-stationary surface convergence zone will be near Havre,
Lewistown, Miles City, the SE corner of Montana today and tonight.
This area will be the focus for showers and thunderstorms. With
very moist atmosphere and precipitable water near 1.3 inches,
very heavy rain will occur in some of these storms with flash
flooding potential. The heaviest rains are expected to be in the
SW part of the forecast area south of Zortman and west of Jordan where
WPC has a moderate risk of excessive rain. There is a slight risk
of excessive rain today and tonight generally south of Malta,
Glasgow, and Richey and west of Wibaux with a marginal risk to the
north and east. Will maintain going Flash Flood Watch over the
western half of the forecast area for today and tonight. The SW
will have the highest chances for showers and thunderstorms today
and tonight and the NE will have the lowest chances.

The convergence zone drifts to the west on Saturday. The NE part
of the forecast area will be dry on Saturday with a surface high
over SE Saskatchewan while showers and thunderstorms continue over
the SW part with heavy rain possible.

An upper level high moves into eastern Montana on Sunday and the
surface convergence area drift far enough west that most of the
forecast area will be dry with precipitation chances limited to
near Zortman and Winnett in the SW. The upper level high remains
over the area on Monday limiting precipitation chances to west of
Malta and Jordan.

This high turns into a ridge on Tuesday and moves to the east on
Wednesday with chances for showers and thunderstorms returning to
the forecast area with an upper trough on Thursday.

&&

.AVIATION...

UPDATED: 0800Z

FLIGHT CAT: VFR to brief MVFR or IFR under thunderstorms.

DISCUSSION: Expect showers and thunderstorms at times today and
tonight which will be most frequent at KGDV and less frequent to
the north. Heavy rain is possible under any thunderstorm.
In between storms, look for mid and high clouds with breaks.

WINDS: E-NE 5-15 knots, higher gusts possible near storms.

&&

.HYDROLOGY...

A moderate risk for Excessive Rain exists over Phillips and
Petroleum Counties with a slight risk of Excessive Rain over the
southern half of the CWA. Will maintain the Flash Flood Watch for
today and tonight from Valley, Garfield, Phillips and Petroleum
Counties. The best chances for heavy rain today and tonight will
be over the SW half of the forecast area.

The Musselshell River at Mosby is forecasted to rise over Action
Stage, but rises into Flood Stage will be possible with this
event. Small streams will likely rise and could cause flooding on
area roads. Rises in the Milk River are also possible as these
streams drain into it.

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Flood Watch through late tonight for Central and Southeast
Phillips...Central and Southern Valley...Garfield...Northern
Phillips...Northern Valley...Petroleum...Southwest Phillips.

&&

weather.gov/glasgow

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

1 flood. Local standard time, as filed.

Flood, Garfield

When: June 9, 11:13 AM MST to 9:24 PM MST
Where: Garfield County, 1.01 mi W of Mosby to 0.82 mi WSW of Mosby
Cause: Heavy Rain
Reported by: River/Stream Gage
Coordinates: 47.001, -107.891

The Musselshell River at Mosby (MSBM8) rose above its flood stage of 10 feet at 11:13 AM on June 9th. The river crested at 10.68 feet at 1:31 PM. The river would briefly go below flood stage at 5:42 PM on June 9th before rising back above flood stage at 6:42 PM on June 9th. The river would eventually fall below flood stage at 9:24 PM on June 9th.

What these are

Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Montana in 2023 Every state in 2023 This day in weather history Warnings in Montana, June 2023

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1105466.