Flash Flood and Hail in Montana, May 24 to 25, 2023

Name: Flash Flood and Hail in Montana, May 24 to 25, 2023
Start: 2023-05-24T16:34
End: 2023-05-25T23:05
Location: Montana

May 24 to 25, 2023 · NWS GGW · 4 events in 2 counties and zones

A pacific disturbance would end up setting off another round of thunderstorms, with some reaching severe levels.

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 4

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.

A pacific disturbance would end up setting off another round of thunderstorms, with some reaching severe levels.

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 May 24, 1:53 PM MST, 2 hours 41 minutes earlier.

Area forecast discussion, May 24, 1:53 PM MST, 2 hours 41 minutes before

Area Forecast Discussion
National Weather Service Glasgow MT
253 PM MDT Wed May 24 2023

.DISCUSSION...
Afternoon Discussion:
Today through tonight:
The air mass over the area continues to destabilize, and some
isolated locations already have storms beginning to fire. A north-
south oriented surface boundary over Phillips and eastern
Petroleum counties will continue to move eastward, so storm
coverage will increase into the early evening hours relative to
this boundary. SB CAPE values are between 1000 and 2000 J/kg and
bulk shear from 0 to 6 km is between 20 and 25 knots. The low wind
shear and PWAT values from 1 to 1.2, isolated areas of flash
flooding are possible today, especially with and slow-moving or
training storms. There is moderate confidence (50 percent) that
some storms will produce severe hail and wind (hail 1 inch in
diameter or greater, and winds gusting 58 mph or more).

Thursday and Friday:
Each afternoon, there is moderate confidence (50 percent) of
thunderstorms occurring in northeast MT. Storm coverage is likely
to cover locations along the ND/MT border on Thursday afternoon,
and coverage is likely to occur further west, possibly as far west
as Phillips and Petroleum county. Small hail, heavy rain, strong
wind gusts, and lightning are likely with any of the storms that
occur.

Saturday onward:
There is low confidence (30 percent) in the severity of
thunderstorms occurring this weekend. However, rain showers appear
likely through Saturday night based on the NBM guidance, with a
lower probability of precipitation afterward. There is a hint of
this stormy pattern being replaced by a ridge by Tuesday, but
uncertainty is still high with this scenario.

-Stoinskers

&&

.AVIATION...

LAST UPDATE: 2100Z

FLIGHT CAT: VFR. Temp MVFR Possible.

DISCUSSION: Isolated to scattered thunderstorms and convection will
move north through NE Montana today and tonight. KGGW and KOLF
are likely to be affected by thunderstorms, and KGDV and KSDY are
less likely to occur this evening. Erratic and gusty winds will
be the biggest impact. Bulk of the forecast is VFR. Terminals that
receive a direct hit from a thunderstorm, especially this
afternoon, may drop to MVFR visibility very briefly due to
moderate rain (RA).

WIND: Southeast at 10 to 20 kts through the day, becoming light
and variable after sundown. On Thursday, northwest winds 5 to 10 for
KGGW. West winds 5 to 10 for KOLF. Southwest winds 5 to 10 knots
for KSDY and KGDV.

-Stoinskers

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

weather.gov/glasgow

In the hours before

Special weather statement, May 24, 2:16 PM MST, 2 hours 18 minutes before

Special Weather Statement
National Weather Service Glasgow MT
316 PM MDT Wed May 24 2023

MTZ017-022-023-242215-
Garfield MT-McCone MT-Central and Southern Valley MT-
316 PM MDT Wed May 24 2023

...A strong thunderstorm will impact portions of northeastern
Garfield, south central Valley and northwestern McCone Counties
through 415 PM MDT...

At 315 PM MDT, Doppler radar was tracking a strong thunderstorm near
The Pines Rec Area, or 31 miles south of Glasgow, moving north at 30
mph.

HAZARD...Winds in excess of 30 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Glasgow, Fort Peck, The Pines Rec Area, Fort Peck Marina, Duck Creek
Rec Area, Park Grove and Whatley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

If on or near the main arm of Fort Peck Lake, get out of the water
and move indoors or inside a vehicle. Remember, lightning can strike
out to 10 miles from the parent thunderstorm. If you can hear
thunder, you are close enough to be struck by lightning. Move to
safe shelter now! Do not be caught on the water in a thunderstorm.

&&

LAT...LON 4765 10647 4766 10674 4823 10678 4823 10638
TIME...MOT...LOC 2115Z 181DEG 24KT 4774 10661

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH

Jamba

Special weather statement, May 24, 2:23 PM MST, 2 hours 11 minutes before

Special Weather Statement
National Weather Service Glasgow MT
323 PM MDT Wed May 24 2023

MTZ021-242215-
Petroleum MT-
323 PM MDT Wed May 24 2023

...A strong thunderstorm will impact portions of southwestern
Petroleum County through 415 PM MDT...

At 321 PM MDT, Doppler radar was tracking a strong thunderstorm 11
miles west of Flatwillow, or 19 miles southwest of Winnett, moving
east at 20 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Winnett and Flatwillow.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4684 10863 4684 10861 4691 10861 4703 10837
      4676 10824 4675 10863
TIME...MOT...LOC 2121Z 256DEG 17KT 4680 10864

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

Enriquez

Special weather statement, May 24, 2:48 PM MST, 1 hour 46 minutes before

Special Weather Statement
National Weather Service Glasgow MT
348 PM MDT Wed May 24 2023

MTZ017-022-023-242245-
Garfield MT-McCone MT-Central and Southern Valley MT-
348 PM MDT Wed May 24 2023

...Strong thunderstorms will impact portions of northeastern
Garfield, south central Valley and northwestern McCone Counties
through 445 PM MDT...

At 347 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 14 miles south of The Pines Rec Area to 10
miles west of Flowing Wells Rest Area. Movement was northeast at 25
mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Fort Peck, The Pines Rec Area, Fort Peck Marina, Duck Creek Rec Area,
Nelson Creek Rec Area, Rock Creek Rec Area, Haxby and Van Norman.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4804 10665 4798 10587 4726 10630 4735 10668
TIME...MOT...LOC 2147Z 217DEG 20KT 4763 10653 4735 10639

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

Enriquez

Special weather statement, May 24, 3:35 PM MST, 59 minutes before

Special Weather Statement
National Weather Service Glasgow MT
435 PM MDT Wed May 24 2023

MTZ016-017-059-061-242330-
Central and Southeast Phillips MT-Northern Valley MT-
Northern Phillips MT-Central and Southern Valley MT-
435 PM MDT Wed May 24 2023

...Strong thunderstorms will impact portions of northeastern Phillips
and northwestern Valley Counties through 530 PM MDT...

At 434 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 6 miles southeast of Whitewater to 24 miles
southwest of Hinsdale. Movement was northeast at 25 mph.

HAZARD...Winds in excess of 40 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Saco, Hinsdale, Vandalia, Frenchman Reservoir and Sleeping Buffalo.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4900 10707 4831 10685 4804 10739 4864 10766
      4900 10734
TIME...MOT...LOC 2234Z 216DEG 21KT 4869 10753 4807 10732

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

Stoinski

Special weather statement, May 24, 3:56 PM MST, 38 minutes before

Special Weather Statement
National Weather Service Glasgow MT
456 PM MDT Wed May 24 2023

MTZ022-250000-
Garfield MT-
456 PM MDT Wed May 24 2023

...A strong thunderstorm will impact portions of central Garfield
County through 600 PM MDT...

At 456 PM MDT, Doppler radar was tracking a strong thunderstorm 7
miles east of Edwards, or 18 miles southwest of Jordan, moving north
at 25 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Jordan and Brusett.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4704 10707 4705 10727 4754 10731 4749 10678
TIME...MOT...LOC 2256Z 184DEG 21KT 4713 10718

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

Enriquez

Special weather statement, May 24, 4:16 PM MST, 18 minutes before

Special Weather Statement
National Weather Service Glasgow MT
516 PM MDT Wed May 24 2023

MTZ016-017-022-059-061-250015-
Garfield MT-Central and Southeast Phillips MT-Northern Valley MT-
Northern Phillips MT-Central and Southern Valley MT-
516 PM MDT Wed May 24 2023

...Strong thunderstorms will impact portions of northeastern
Phillips, central Garfield and western Valley Counties through 615 PM
MDT...

At 516 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 11 miles east of Whitewater to 12 miles
northeast of Saco to 16 miles northwest of Hell Creek Rec Area.
Movement was northeast at 30 mph.

HAZARD...Winds in excess of 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Glasgow, Tampico, Hinsdale, St. Marie, Vandalia, Thoeny, The
Bentonite Plant, Frenchman Reservoir and Whatley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4900 10652 4814 10646 4764 10729 4848 10727
      4870 10751 4900 10733
TIME...MOT...LOC 2316Z 206DEG 25KT 4875 10737 4859 10716 4774 10718

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

Stoinski

The radar

The Glasgow radar (KGGW), 42 km away, was scanning. The volume nearest the first event began at 23:35 UTC.

Open the radar archive at this moment

Event by event

2 heavy rain, 1 hail, 1 flash flood. Local standard time, as filed.

Heavy Rain, Valley

When: May 24, 4:34 PM MST
Where: Valley County, 4.72 mi SW of Hinsdale
Reported by: Trained Spotter
Coordinates: 48.350, -107.150

A trained spotter reported 1-1/2 inches of rain falling within 25 minutes.

Heavy Rain, Valley

When: May 24, 4:51 PM MST
Where: Valley County, 15.36 mi NNW of Hinsdale
Reported by: Trained Spotter
Coordinates: 48.610, -107.190

A trained spotter estimated about 1 inch of rain within 30 minutes with lots of standing water on a nearby farm.

Hail, Dawson

When: May 25, 6:55 PM MST
Where: Dawson County, 1.17 mi NE of Glendive
Measured: 1 in hail
Reported by: Trained Spotter
Coordinates: 47.110, -104.710

A trained spotter reported hail up to the size of quarters.

Flash Flood, Valley

When: May 25, 11:05 PM MST
Where: Valley County, 0.37 mi WSW of Glasgow to 0.45 mi SW of Glasgow
Cause: Heavy Rain
Reported by: Law Enforcement
Coordinates: 48.197, -106.637

Law enforcement reported flooding under the 6th St. underpass with a vehicle stuck in the flood waters.

What these are

Heavy Rain: Rainfall totals unusual for the place and season that did not produce a flood.
Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

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, May 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: 1093530, 1093531, 1093527, 1093524.