Flash Flood and Hail in Montana, July 18, 2001

Name: Flash Flood and Hail in Montana, July 18, 2001
Start: 2001-07-18T01:00
End: 2001-07-18T19:57
Location: Montana

July 18, 2001 · NWS BYZ · 21 events in 7 counties and zones

Damage to home in Broadus, Montana from baseball to softball size hail that fell on the evening of July 18, 2001.

Where it happened

Every event with a place to put it; 5 filed by county or forecast zone are drawn at its center, in a lighter ring. 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: 21

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 BYZ wrote it up.

Damage to home in Broadus, Montana from baseball to softball size hail that fell on the evening of July 18, 2001.

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 Billings, MT wrote its last area forecast discussion before the first event at Jul 17, 7:10 PM MST, 5 hours 50 minutes earlier.

Area forecast discussion, Jul 17, 7:10 PM MST, 5 hours 50 minutes before

SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
810 PM MDT TUE JUL 17 2001

.WED AND THU...
WILL CLEAR OUT WESTERN ZONES OUT OF WATCH WITH AN SPS. SEVERE WEATHER
THREAT PRIMARILY WILL BE IN FAR EASTERN ZONES...BUT WITH SFC HEATING
DECREASING STORMS WILL CONTINUE TO WEAKEN. MAY SEE AN ISOLATED SEVERE
STORM BEFORE 10 PM IN REMAIN WATCH ZONES.

WILL MAKE SOME ADJUSTMENTS TO POPS TO REFLECT TRENDS. TEMPS LOOK GOOD.
SCARLETT

.FRI...SAT...SUN...MON...TUE...
THE UPPER TROUGH OVER THE PACIFIC NORTHWEST SPLITS WITH ENERGY SINKING
SOUTHWARD TO NORTHERN CALIFORNIA OVER THE WEEKEND. THIS IN TURN
INCREASES THE UPPER RIDGE A LITTLE OVER MONTANA...NET RESULT...WARMING
TEMPERATURES. WITH THE FLOW ALOFT FROM THE SOUTHWEST...AFTERNOON AND
EVENING THUNDERSTORMS ARE POSSIBLE. BEST CHANCES APPEAR EARLY ON AS PART
OF THE SPLIT ENERGY TRAVERSES OUR AREA FRIDAY. TOWARD THE END OF THE
EXTENDED...THE NORTHERN CALIFORNIA TROUGH LIFTS OUT TO THE NORTHEAST
ONCE AGAIN GIVING US A BETTER CHANCE OF LATE DAY STORMS. CANEPA

    WED     THU     FRI     SAT     SUN     MON     TUE
-----------------------------------------------------------
BIL 058/081 056/085 058/085 060/085 060/088 060/088 057/083
    33/T    32/T    33/T    22/B    22/B    22/B    33/T
LVM 050/078 048/082 054/082 056/084 056/087 056/087 055/084
    33/T    33/T    33/T    22/B    22/B    22/B    33/T
HDN 056/083 054/087 057/087 059/087 059/090 059/090 058/087
    33/T    32/T    33/T    22/B    22/B    22/B    33/T
MLS 060/086 060/090 060/088 062/088 062/091 062/091 059/085
    33/T    32/T    33/T    22/B    22/B    22/B    33/T
4BQ 059/085 059/089 059/088 061/088 061/091 061/091 058/087
    33/T    32/T    33/T    22/B    22/B    22/B    33/T
BHK 058/084 058/088 058/087 060/087 060/090 060/090 056/088
    33/T    32/T    33/T    22/B    22/B    22/B    33/T
SHR 052/083 050/087 056/08T5 058/085 058/088 058/088 053/083
    23/T    33/T    33/T    22/B    22/B    22/B    33/T

In the hours before

Special weather statement, Jul 17, 7:20 PM MST, 5 hours 40 minutes before

MTZ028>030-034-035-038>042-056-057-180400-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BILLINGS MT
820 PM MDT TUE JUL 17 2001

...SEVERE THUNDERSTORM WATCH UNTIL 10 PM MDT FOR PORTIONS OF SOUTH
   CENTRAL AND CENTRAL MONTANA HAS BEEN CANCELED...

THE SEVERE THUNDERSTORM WATCH FOR PORTIONS OF SOUTHERN MONTANA HAS BEEN
CANCELED. COUNTIES CLEARED FROM THE WATCH ARE...PARK...SWEET GRASS...
WHEATLAND...GOLDEN VALLEY...STILLWATER...CAhRBON...BIG HORN...
YELLOWSTONE...MUSSELSHELL AND TREASURE. THUNDERSTORMS IN THESE AREAS
HAVE WEAKENED...AND THE THREAT OF SEVERE WEATHER HAS DIMINISHED.

Local storm report, Jul 17, 9:15 PM MST, 3 hours 45 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS, MT
1015 PM MDT TUE JUL 17 2001

TIME(MDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0155 PM    10 S TWO DOT              MT   1.00 INCH HAIL
07/17/01   WHEATLAND

0205 PM    10 S TWO DOT              MT   1.00 INCH HAIL
07/17/01   WHEATLAND

0220 PM    HARLOWTON                 MT   .75 INCH HAIL
07/17/01   WHEATLAND

0230 PM    HARLOWTON                 MT   .88 INCH HAIL
07/17/01   WHEATLAND

0313 PM    1 W MELVILLE              MT   .75 INCH HAIL
07/17/01   SWEET GRASS

0328 PM    18 NW RYEGATE             MT   .75 INCH HAIL
07/17/01   GOLDEN VALLEY

0420 PM    27 N LAVINA               MT   .88 INCH HAIL
07/17/01   MUSSELSHELL                    NICKEL SIZE HAIL 2 FEET
                                          DEEP

0700 PM    15 N SUMATRA              MT   .75 INCH HAIL
07/17/01   ROSEBUD

0800 PM    MELSTONE                  MT   FLOOD
07/17/01   MUSSELSHELL                    3-4 FEET OF WATER RUNNING
                                          OVER HIGHWAY. FLOODING
                                          LASTED UNTIL 1000 PM MDT.

JRS

The radar

The Glasgow radar (KGGW), 231 km away, was scanning. The volume nearest the first event began at 08:00 UTC.

Open the radar archive at this moment

Event by event

15 hail, 5 thunderstorm wind, 1 flash flood. Local standard time, as filed.

Hail, Fallon

When: July 18, 1:00 AM MST
Where: Fallon County, 25 mi NW of Baker
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 46.617, -104.650

Hail, Big Horn

When: July 18, 3:03 PM MST
Where: Big Horn County, 1 mi W of Hardin
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 45.733, -107.617

Hail covered the ground

Hail, Big Horn

When: July 18, 3:05 PM MST
Where: Big Horn County, Hardin
Measured: 1.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 45.733, -107.600

Hail, Big Horn

When: July 18, 3:10 PM MST
Where: Big Horn County, 2 mi N of Hardin
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 45.767, -107.600

Hail, Musselshell

When: July 18, 3:15 PM MST
Where: Musselshell County, Melstone
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 46.600, -107.883

Hail, Rosebud

When: July 18, 3:20 PM MST
Where: Rosebud County, 12 mi W of Sumatra
Measured: 1 in hail
Reported by: TRAINED SPOTTER
Coordinates: 46.617, -107.800

Hail, Rosebud

When: July 18, 4:20 PM MST
Where: Rosebud County, 14 mi S of Colstrip
Measured: 1 in hail
Reported by: TRAINED SPOTTER
Coordinates: 45.683, -106.583

Hail, Custer

When: July 18, 4:50 PM MST
Where: Custer County, 15 mi S of Mizpah
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 46.033, -105.267

Hail, Rosebud

When: July 18, 5:00 PM MST
Where: Rosebud County, Brandenberg
Measured: 0.88 in hail
Reported by: TRAINED SPOTTER
Coordinates: 45.833, -106.183

Hail, Fallon

When: July 18, 5:00 PM MST
Where: Fallon County, 25 mi W of Willard
Measured: 1.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 46.200, -104.883

Hail, Carter

When: July 18, 5:17 PM MST
Where: Carter County, 24 mi NW of Ekalaka
Measured: 1.25 in hail
Reported by: TRAINED SPOTTER
Coordinates: 46.133, -104.900

Hail, Fallon

When: July 18, 5:50 PM MST
Where: Fallon County, 20 mi SW of Baker
Measured: 0.88 in hail
Reported by: TRAINED SPOTTER
Coordinates: 46.167, -104.583

Hail, Powder River

When: July 18, 6:10 PM MST
Where: Powder River County, Broadus
Measured: 4.5 in hail
Reported by: TRAINED SPOTTER
Coordinates: 45.450, -105.417

Supercell thunderstorms (mainly large hail producers) developed across the eastern half of the NWS Billings County Warning Area around 3:30 pm on July 18th and continued until 9:30 pm. Baseball to softball size hail fell in Broadus, Montana. Numerous car windshields and house windows were smashed. In addition...vinyl siding was stripped from houses, metal roofs were severely dented...and many trees throughout town were stripped of their leaves. The Broadus Elementary and High Schools had approximately 60 to 70 windows broken. Several private business establishment had their outdoor signs broken. The Powder River Nursing Home also had all the windows on the west side of the building broken.

Hail, Fallon

When: July 18, 6:35 PM MST
Where: Fallon County, 25 mi SE of Baker
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 46.117, -103.917

Thunderstorm Wind, Carter

When: July 18, 7:00 PM MST
Where: Carter County, 24 mi SW of Ekalaka
Reported by: TRAINED SPOTTER
Coordinates: 45.517, -104.536 (the zone’s center; the record gives no point)

70 mph thunderstorm wind gust with dime size hail...2 foot diameter trees downed

Thunderstorm Wind, Carter

When: July 18, 7:15 PM MST
Where: Carter County, 44 mi S of Ekalaka
Measured: 60 kt (69 mph)
Reported by: TRAINED SPOTTER
Coordinates: 45.250, -104.550

Flash Flood, Powder River

When: July 18, 7:15 PM MST
Where: Powder River County, 5 mi W of Broadus
Reported by: LAW ENFORCEMENT
Coordinates: 45.395, -105.630 (the zone’s center; the record gives no point)

Water over Highway 212

Thunderstorm Wind, Carter

When: July 18, 7:20 PM MST
Where: Carter County, 20 mi S of Ekalaka
Reported by: TRAINED SPOTTER
Coordinates: 45.517, -104.536 (the zone’s center; the record gives no point)

60 mph thunderstorm wind gust with dime sized hail

Thunderstorm Wind, Carter

When: July 18, 7:22 PM MST
Where: Carter County, 10 mi S of Ekalaka
Reported by: TRAINED SPOTTER
Coordinates: 45.517, -104.536 (the zone’s center; the record gives no point)

70 mph thunderstorm wind gust with nickel size hail

Thunderstorm Wind, Carter

When: July 18, 7:25 PM MST
Where: Carter County, 30 mi S of Ekalaka
Reported by: TRAINED SPOTTER
Coordinates: 45.517, -104.536 (the zone’s center; the record gives no point)

65 mph thunderstorm winds with nickel size hail

Hail, Carter

When: July 18, 7:57 PM MST
Where: Carter County, 4 mi NE of Mill Iron
Measured: 0.88 in hail
Reported by: TRAINED SPOTTER
Coordinates: 45.883, -104.150

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
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 2001 Every state in 2001 This day in weather history Warnings in Montana, July 2001

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: 5259601, 5259602, 5259603, 5259604, 5259605, 5259606, 5259607, 5259614, 5259608, 5259609, 5259610, 5259611, 5259612, 5259613, 5259682, 5259615, 5259685, 5259616, 5259681, 5259684, 5259683.