Alert archive / Montana / Flash Flood Warnings in 2026

Flash Flood Warning 5, NWS Great Falls, MT

July 17, 2026Broadwater County, Lewis and Clark County, Montana

NWS Great Falls, MT issued this flash flood warning at Jul 17, 2026, 9:06 PM MDT for Broadwater County, Lewis and Clark County, Montana. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Jul 17, 2026, 9:06 PM MDT (03:06 UTC)
Expired: Jul 18, 2026, 1:00 AM MDT
In force: 4 hr
Issued by: NWS Great Falls, MT
Area: Storm-based polygon
Flood severity: None

Counties Broadwater County, MT, Lewis and Clark County, MT

The radar

The Great Falls radar (KTFX), 88 km from the middle of the area, began a volume at 03:07 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this flash flood warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Glasgow Intl Airport, MT (KGGW), launched 00:00Z, 3.1 hours before the alert went out and 417 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2796 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 67 m²/s²
0-3 km storm-relative helicity: 94 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

The text

As transmitted.

798 
WGUS55 KTFX 180306
FFWTFX
MTC007-049-180700-
/O.NEW.KTFX.FF.W.0005.260718T0306Z-260718T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Great Falls MT
906 PM MDT Fri Jul 17 2026

The National Weather Service in Great Falls has issued a

* Flash Flood Warning for...
  The Horse Gulch burn scar in...
  Northwestern Broadwater County in southwestern Montana...
  Southeastern Lewis and Clark County in west central Montana...

* Until 100 AM MDT.

* At 906 PM MDT, Doppler radar indicated heavy rain over the Horse
  Gulch Burn Scar. Up to 1 inch of rain has fallen. The expected
  rainfall rate is 0.5 inches in 1 hour. Flash flooding is ongoing or
  expected to begin shortly. Excessive rainfall over the burn scar
  will result in debris flow moving through the Some drainage basins
  impacted include... The debris flow can consist of rock, mud,
  vegetation and other loose materials.

  HAZARD...Flash flooding caused by heavy rain in and around the
           Horse Gulch Burn Scar.

  SOURCE...Radar indicated.

  IMPACT...Flooding of areas in and around the Horse Gulch Burn Scar.

* Some locations that will experience flash flooding include...
  Mainly rural areas of Northwestern Broadwater and Southeastern
  Lewis and Clark Counties.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a life-threatening situation...

Move to higher ground now. Act quickly to protect your life.

&&

LAT...LON 4669 11174 4670 11171 4671 11171 4671 11168
      4673 11167 4673 11166 4672 11166 4672 11163
      4670 11161 4670 11159 4669 11159 4669 11160
      4665 11160 4665 11166 4666 11166 4666 11169
      4667 11169 4667 11172 4666 11172 4666 11173

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...0.5 INCHES IN 1 HOUR

$$

ML

1 follow-up statement

883 
WGUS75 KTFX 180657
FFSTFX

Flash Flood Statement
National Weather Service Great Falls MT
1257 AM MDT Sat Jul 18 2026

MTC007-049-180707-
/O.EXP.KTFX.FF.W.0005.000000T0000Z-260718T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Broadwater MT-Lewis and Clark MT-
1257 AM MDT Sat Jul 18 2026

...FLASH FLOOD WARNING FOR THE HORSE GULCH BURN SCAR WILL EXPIRE AT 1
AM MDT EARLY THIS MORNING...

The heavy rain has ended and flood waters are receding. Flooding is
no longer expected to pose a threat. Please continue to heed
remaining road closures.

&&

LAT...LON 4669 11174 4670 11171 4671 11171 4671 11168
      4673 11167 4673 11166 4672 11166 4672 11163
      4670 11161 4670 11159 4669 11159 4669 11160
      4665 11160 4665 11166 4666 11166 4666 11169
      4667 11169 4667 11172 4666 11172 4666 11173

$$

RCG

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Great Falls, MT wrote its last area forecast discussion before this flash flood warning went out at Jul 17, 6:11 PM MDT, 2 hours 55 minutes earlier. Its key messages:

Scattered to numerous showers and thunderstorms will move in a southwest to northeast fashion later this afternoon through the early overnight hours.
Thunderstorm hazards will include strong, gusty winds, hail, and torrential downpours capable of localized flooding.
Warmer temperatures and slightly drier conditions move in for the weekend, although there will still be widely scattered shower and thunderstorm activity.

Area forecast discussion, Jul 17, 6:11 PM MDT, 2 hours 55 minutes before

Area Forecast Discussion
National Weather Service Great Falls MT
Issued by National Weather Service Missoula MT
611 PM MDT Fri Jul 17 2026

Aviation Section Updated.

.KEY MESSAGES...

 - Scattered to numerous showers and thunderstorms will move in a
   southwest to northeast fashion later this afternoon through the
   early overnight hours.

 - Thunderstorm hazards will include strong, gusty winds, hail,
   and torrential downpours capable of localized flooding.

 - Warmer temperatures and slightly drier conditions move in for
   the weekend, although there will still be widely scattered
   shower and thunderstorm activity.

&&

.DISCUSSION...
/Issued Issued by National Weather Service Missoula MT/

A shortwave embedded within a southwesterly flow aloft will
interact with monsoon moisture and an unstable profile for the
development of clusters to broken lines of thunderstorms moving
in a southwest to northeast fashion this afternoon into tonight.
The most robust CAPE over 1,500 J/kg will be slightly farther east
of the 30 +kt bulk shear area, but there will certainly enough
overlap for at least scattered strong to severe thunderstorms.
Additionally, anomalously high PWATS, generally between an inch
and an inch and a half, will be capable of producing brief periods
with rainfall rates in the half to one inch range and even higher
in the stronger cores. A flash flood watch was sent out again for
the Horse Gulch Burn scar for this afternoon and evening. Urban
areas that receive these heavier rainfall rates will also be
susceptible to localized flooding, especially over central and
north-central MT, though confidence was not quite high enough for
additional flood products at this time.

Slightly drier air moves in for the weekend as the flow aloft
becomes more westerly and pushes the richest moisture off to the
east. There will be another shortwave that passes through again
on Saturday, but it will have less CAPE and moisture to interact
with. The widely scattered showers and storms that do develop
will contain gusty, to locally strong winds with RH's dropping
back down to the teens Saturday afternoon. Similar conditions
prevail for Sunday, though storm coverage may be even less than
Saturday.

Aside from a brief cooldown on Monday thanks to a passing cold
front, temperatures will be on the rise thanks to high pressure
aloft building over the Great Basin area. The Northern Rockies
will still be far enough north for shortwaves and moisture to
compromise the high and bring at least widely scattered shower and
thunderstorm activity. - RCG

&&

.AVIATION...
18/00Z TAF Period

Showers remain in the area with thunderstorms lingering over the
Lewis Range and pushing eastward. Easterly winds at the surface
from KGTF eastward this evening will shift to west southwest as
the frontal boundary moves through. Expect showers and
thunderstorms to push to the north northeast. Showers and
thunderstorms will be the most widespread until around 06Z Sun
when high resolution models show them becoming more scattered and
dissipating to the north. Radar shows some gusty outflow
boundaries stemming from the bulk of the storms which may impact
areas around KGTF and KHLN through 02Z Sat. Temporary strong
northwest winds possible with these storms. Overnight, skies will
clear slowly which will increase radiational cooling. Areas that
received rain and then clear will see some patchy fog, but
widespread dense fog is less of a concern this evening. There is
around a 10-15% chance of IFR CIGs around KCTB from 08Z-14Z Sat,
which is one area that models are highlighting. A return of
showery conditions is possible after 20Z Sat, but not expected to
be as widespread as this evening.      -Muessle

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  95  61  95  61 /  20  90  10  20
CTB  90  60  91  57 /  30  70  10   0
HLN  94  62  93  61 /  50  70  30  30
BZN  93  57  92  57 /  30  70  20  20
WYS  85  48  87  48 /  50  80  20  10
DLN  88  55  89  55 /  70  70  20  10
HVR  98  64  97  63 /   0  70  20  20
LWT  90  56  89  57 /  10  60  20  20

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until midnight MDT tonight for Big Belt,
Bridger and Castle Mountains.

&&

http://www.weather.gov/greatfalls

In the hours before

Local storm report, Jul 17, 7:00 PM MDT, 2 hours 6 minutes before

Preliminary Local Storm Report
National Weather Service Great Falls MT
700 PM MDT Fri Jul 17 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0650 PM     Tstm Wnd Gst     7 SSE Ulm               47.33N 111.48W
07/17/2026  M56 MPH          Cascade            MT   Trained Spotter

&&

JTG

Special weather statement, Jul 17, 7:08 PM MDT, 1 hour 58 minutes before

Special Weather Statement
National Weather Service Great Falls MT
708 PM MDT Fri Jul 17 2026

MTZ319-320-322-323-180200-
Helena Valley MT-Elkhorn and Boulder Mountains MT-
Big Belt, Bridger and Castle Mountains MT-Canyon Ferry Area MT-
708 PM MDT Fri Jul 17 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN LEWIS AND CLARK...
NORTHWESTERN BROADWATER AND NORTHEASTERN JEFFERSON COUNTIES THROUGH
800 PM MDT...

At 707 PM MDT, Doppler radar was tracking a strong thunderstorm near
Townsend, moving northwest at 25 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
Townsend, Silos, Winston, and Goose Bay.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

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.

&&

LAT...LON 4637 11126 4626 11146 4652 11189 4668 11159
TIME...MOT...LOC 0107Z 138DEG 20KT 4638 11145

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

Glinskas

Local storm report, Jul 17, 7:30 PM MDT, 1 hour 36 minutes before

Preliminary Local Storm Report
National Weather Service Great Falls MT
730 PM MDT Fri Jul 17 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0652 PM     Tstm Wnd Gst     8 SSE Ulm               47.32N 111.47W
07/17/2026  M72 MPH          Cascade            MT   AWOS

            AWOS station K1IM India.

&&

PN

Special weather statement, Jul 17, 8:00 PM MDT, 1 hour 6 minutes before

Special Weather Statement
National Weather Service Great Falls MT
800 PM MDT Fri Jul 17 2026

MTZ317-321-180245-
Little Belt and Highwood Mountains MT-Meagher County Valleys MT-
800 PM MDT Fri Jul 17 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN MEAGHER COUNTY
THROUGH 845 PM MDT...

At 759 PM MDT, Doppler radar was tracking a strong thunderstorm 24
miles northwest of White Sulphur Springs, moving northeast at 15 mph.

HAZARD...Wind gusts up to 50 mph and half inch hail.

SOURCE...Radar indicated.

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

This storm will remain over mainly rural areas of northwestern
Meagher County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

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.

&&

LAT...LON 4674 11128 4684 11144 4702 11112 4683 11086
TIME...MOT...LOC 0159Z 236DEG 15KT 4683 11122

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

Glinskas

Special weather statement, Jul 17, 8:08 PM MDT, 58 minutes before

Special Weather Statement
National Weather Service Great Falls MT
808 PM MDT Fri Jul 17 2026

MTZ312-180300-
Cascade County below 5000ft MT-
808 PM MDT Fri Jul 17 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN JUDITH BASIN...
SOUTHWESTERN CHOUTEAU AND NORTHEASTERN CASCADE COUNTIES THROUGH 900
PM MDT...

At 808 PM MDT, Doppler radar was tracking a strong thunderstorm near
Belt, or 21 miles southeast of Great Falls, moving north at 15 mph.

HAZARD...Wind gusts up to 50 mph and half inch hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Belt and Armington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 4755 11094 4755 11089 4752 11086 4752 11077
      4745 11077 4739 11071 4736 11074 4735 11077
      4731 11077 4723 11083 4722 11086 4728 11109
      4758 11100
TIME...MOT...LOC 0208Z 199DEG 13KT 4732 11094

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

Ludwig

Local storm report, Jul 17, 8:11 PM MDT, 55 minutes before

Preliminary Local Storm Report
National Weather Service Great Falls MT
811 PM MDT Fri Jul 17 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0700 PM     Rain             7 SSE Ulm               47.33N 111.48W
07/17/2026  M1.13 Inch       Cascade            MT   Trained Spotter

            Rainfall total between 6:35 PM and 7 PM.

&&

JTG

The office that day

Everything else NWS Great Falls, MT issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 17, 6:25 PM MDT	Special Weather Statement	TFX	Jefferson	50 min
Jul 17, 6:41 PM MDT	Areal Flood Advisory	TFX	Jefferson	3 hr
Jul 17, 6:47 PM MDT	Special Weather Statement	TFX	Cascade	43 min
Jul 17, 6:58 PM MDT	Severe Thunderstorm Warning	TFX	Cascade, Chouteau, Teton	32 min
Jul 17, 7:08 PM MDT	Special Weather Statement	TFX	Broadwater	52 min
Jul 17, 7:26 PM MDT	Severe Thunderstorm Warning	TFX	Broadwater, Meagher	37 min
Jul 17, 8:00 PM MDT	Special Weather Statement	TFX	Meagher	45 min
Jul 17, 8:08 PM MDT	Special Weather Statement	TFX	Cascade	52 min
Jul 17, 8:33 PM MDT	Areal Flood Advisory	TFX	Broadwater, Meagher	3 hr
Jul 17, 8:35 PM MDT	Areal Flood Advisory	TFX	Cascade, Judith Basin	3 hr
Jul 18, 1:46 PM MDT	Special Weather Statement	TFX	Beaverhead	44 min
Jul 18, 2:25 PM MDT	Special Weather Statement	TFX	Silver Bow	50 min
Jul 18, 2:32 PM MDT	Severe Thunderstorm Warning	TFX	Beaverhead, Jefferson, Madison	28 min
Jul 18, 2:53 PM MDT	Severe Thunderstorm Warning	TFX	Broadwater, Gallatin, Jefferson, Madison	67 min
Jul 18, 4:01 PM MDT	Special Weather Statement	TFX	Broadwater	59 min
Jul 18, 4:21 PM MDT	Special Weather Statement	TFX	Lewis and Clark	39 min
Jul 18, 4:49 PM MDT	Special Weather Statement	TFX	Beaverhead	56 min
Jul 18, 4:49 PM MDT	Special Weather Statement	TFX	Pondera	26 min
Jul 18, 5:00 PM MDT	Severe Thunderstorm Warning	TFX	Cascade, Lewis and Clark	45 min
Jul 18, 5:09 PM MDT	Special Weather Statement	TFX	Liberty, Pondera	66 min
Jul 18, 5:26 PM MDT	Severe Thunderstorm Warning	TFX	Lewis and Clark, Teton	64 min
Jul 18, 5:30 PM MDT	Severe Thunderstorm Warning	TFX	Liberty, Toole	60 min
Jul 18, 5:41 PM MDT	Special Weather Statement	TFX	Cascade	49 min
Jul 18, 5:44 PM MDT	Areal Flood Advisory	TFX	Liberty, Pondera, Toole	3 hr
Jul 18, 5:48 PM MDT	Severe Thunderstorm Warning	TFX	Pondera, Toole	57 min
Jul 18, 5:50 PM MDT	Special Weather Statement	TFX	Madison	55 min
Jul 18, 5:55 PM MDT	Severe Thunderstorm Warning Considerable damage threat	TFX	Teton	35 min
Jul 18, 5:56 PM MDT	Special Weather Statement	TFX	Cascade	49 min

Nearby

Flash Flood Warnings in Montana, 2026 Every flash flood warning in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.