Montana, 1999

Tornadoes and Hail in Montana, July 21, 1999

July 21, 1999 · NWS GGW · 28 events in 6 counties and zones

Two supercell thunderstorms moved across northeast Montana causing a path of damage that extended from southern Phillips county to the North Dakota border. 5 inch hail fell damaging cars, roofs, windows and trees as it passed.

Where it happened

Every event with a place to put it; 2 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
$1.6 million
Crop damage
$200,000
Events
28

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.

Two supercell thunderstorms moved across northeast Montana causing a path of damage that extended from southern Phillips county to the North Dakota border. The hardest hit was the community of Glasgow where 4.5 inch hail fell damaging cars, roofs, windows and trees as it passed. The largest hail fell from downtown Glasgow near the courthouse northeast to the local Ford dealership. The storms continued east where they produced at least two tornado touchdowns in rural areas. Large hail continued to be reported along the Highway 2 corridor. A tornado touchdown was reported in Bainville where railroad cars were blown off of the tracks.

The radar

The Glasgow radar (KGGW), 26 km away, was scanning. The volume nearest the first event began at 23:38 UTC.

Open the radar archive at this moment

Event by event

21 hail, 3 thunderstorm wind, 2 funnel cloud, 2 tornado. Local standard time, as filed.

Hail, Valley

When
July 21, 4:39 PM MST
Where
Valley County, 15 mi W of Glasgow
Measured
0.88 in hail
Reported by
GENERAL PUBLIC
Coordinates
48.200, -106.970

Hail, Phillips

When
July 21, 4:43 PM MST
Where
Phillips County, Zortman
Measured
0.75 in hail
Reported by
TRAINED SPOTTER
Coordinates
47.920, -108.530

Hail, Phillips

When
July 21, 5:30 PM MST
Where
Phillips County, 22 mi S of Malta
Measured
1.75 in hail
Property damage
$30,000
Reported by
GENERAL PUBLIC
Coordinates
48.030, -107.870

Thunderstorm Wind, Prairie

When
July 21, 5:42 PM MST
Where
Prairie County, Terry
Measured
52 kt (60 mph)
Reported by
LAW ENFORCEMENT
Coordinates
46.780, -105.300

Hail, Phillips

When
July 21, 6:15 PM MST to 6:25 PM MST
Where
Phillips County, 22 mi S of Malta
Measured
1.75 in hail
Reported by
GENERAL PUBLIC
Coordinates
48.030, -107.870

Hail, Valley

When
July 21, 6:25 PM MST
Where
Valley County, 18 mi S of Hinsdale
Measured
1.75 in hail
Reported by
GENERAL PUBLIC
Coordinates
48.130, -107.080

Hail, Valley

When
July 21, 6:40 PM MST
Where
Valley County, Glasgow
Measured
2.5 in hail
Crop damage
$100,000
Reported by
OFFICIAL NWS OBS.
Coordinates
48.200, -106.630

Hail, Valley

When
July 21, 6:40 PM MST
Where
Valley County, 15 mi W of Glasgow
Measured
4 in hail
Property damage
$5,000
Reported by
GENERAL PUBLIC
Coordinates
48.200, -106.970

Funnel Cloud, Valley

When
July 21, 6:45 PM MST
Where
Valley County, 15 mi W of Glasgow
Reported by
GENERAL PUBLIC
Coordinates
48.365, -106.667 (the zone’s center; the record gives no point)

Hail, Valley

When
July 21, 6:50 PM MST
Where
Valley County, Glasgow
Measured
4.5 in hail
Property damage
$1.5 million
Crop damage
$100,000
Reported by
LAW ENFORCEMENT
Coordinates
48.200, -106.630

Hail, Valley

When
July 21, 7:20 PM MST
Where
Valley County, Nashua
Measured
2.5 in hail
Reported by
TRAINED SPOTTER
Coordinates
48.130, -106.350

Hail, Valley

When
July 21, 7:47 PM MST
Where
Valley County, 15 mi SE of Glasgow
Measured
0.88 in hail
Reported by
TRAINED SPOTTER
Coordinates
48.050, -106.400

Hail, Phillips

When
July 21, 8:05 PM MST
Where
Phillips County, 10 mi W of Saco
Measured
0.88 in hail
Reported by
GENERAL PUBLIC
Coordinates
48.470, -107.550

Hail, Valley

When
July 21, 8:15 PM MST
Where
Valley County, 27 mi N of Hinsdale
Measured
0.88 in hail
Reported by
TRAINED SPOTTER
Coordinates
48.780, -107.080

Hail, Roosevelt

When
July 21, 8:45 PM MST
Where
Roosevelt County, 6 mi W of Poplar
Measured
1.75 in hail
Reported by
LAW ENFORCEMENT
Coordinates
48.100, -105.330

Hail, Valley

When
July 21, 8:48 PM MST
Where
Valley County, 12 mi N of Frazer
Measured
1 in hail
Reported by
TRAINED SPOTTER
Coordinates
48.220, -106.030

Hail, Roosevelt

When
July 21, 8:56 PM MST
Where
Roosevelt County, 5 mi W of Wolf Pt
Measured
1 in hail
Reported by
TRAINED SPOTTER
Coordinates
48.100, -105.770

Funnel Cloud, Roosevelt

When
July 21, 8:56 PM MST
Where
Roosevelt County, 5 mi W of Wolf Pt
Reported by
LAW ENFORCEMENT
Coordinates
48.295, -105.016 (the zone’s center; the record gives no point)

Tornado, Roosevelt

When
July 21, 9:47 PM MST
Where
Roosevelt County, 10 mi E of Brockton
Rating
F0
Path length
0.2 mi
Path width
10 yd
Reported by
LAW ENFORCEMENT
Coordinates
48.150, -104.700

Hail, Valley

When
July 21, 9:49 PM MST
Where
Valley County, Opheim
Measured
0.75 in hail
Reported by
TRAINED SPOTTER
Coordinates
48.850, -106.400

Hail, Sheridan

When
July 21, 10:01 PM MST
Where
Sheridan County, Reserve
Measured
0.75 in hail
Reported by
TRAINED SPOTTER
Coordinates
48.600, -104.450

Tornado, Roosevelt

When
July 21, 10:10 PM MST
Where
Roosevelt County, Bainville
Rating
F1
Path length
1 mi
Path width
30 yd
Property damage
$20,000
Reported by
LAW ENFORCEMENT
Coordinates
48.130, -104.220

Thunderstorm Wind, Roosevelt

When
July 21, 10:32 PM MST
Where
Roosevelt County, 3 mi NE of Wolf Pt
Property damage
$10,000
Reported by
LAW ENFORCEMENT
Coordinates
48.130, -105.600

Hail, Valley

When
July 21, 10:40 PM MST
Where
Valley County, 7 mi SE of Glasgow
Measured
0.75 in hail
Reported by
GENERAL PUBLIC
Coordinates
48.130, -106.530

Hail, Roosevelt

When
July 21, 11:10 PM MST
Where
Roosevelt County, Poplar
Measured
0.75 in hail
Reported by
LAW ENFORCEMENT
Coordinates
48.100, -105.200

Hail, Sheridan

When
July 21, 11:13 PM MST
Where
Sheridan County, Reserve
Measured
0.88 in hail
Reported by
TRAINED SPOTTER
Coordinates
48.600, -104.450

Hail, McCone

When
July 21, 11:15 PM MST
Where
McCone County, 15 mi N of Vida
Measured
0.75 in hail
Property damage
$4,000
Reported by
TRAINED SPOTTER
Coordinates
48.050, -105.500

Thunderstorm Wind, Roosevelt

When
July 21, 11:27 PM MST
Where
Roosevelt County, Poplar
Measured
56 kt (64 mph)
Reported by
OFFICIAL NWS OBS.
Coordinates
48.100, -105.200

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.
Funnel Cloud
A rotating column of cloud extending from a thunderstorm that did not reach the ground.
Tornado
A violently rotating column of air in contact with the ground and extending from a thunderstorm, filed with its path, width and Fujita or Enhanced Fujita rating from the damage survey.

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

The same day elsewhere

More

Every storm in Montana in 1999Every state in 1999This day in weather historyThe tornado archive for Montana, 1999Warnings in Montana, July 1999

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 2026-10-01. Each event’s entry at NCEI: 5702688, 5702894, 5702895, 5702897, 5702689, 5702687, 5702690, 5702796, 5702797, 5702691, 5702778, 5702779, 5702794, 5702780, 5702781, 5702782, 5702783, 5702793, 5702784, 5702785, 5702786, 5702787, 5702788, 5702789, 5702790, 5702791, 5702795, 5702792.