Montana, 1999

Flash Flooding and Hail in Montana, August 7, 1999

August 7, 1999 · NWS BYZ · 3 events in 3 counties and zones

2 flash flood, 1 hail, as filed by the National Weather Service.

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

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The toll

Deaths
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
3

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.

The radar

The Billings radar (KBLX), 21 km away, was scanning. The volume nearest the first event began at 01:30 UTC.

Open the radar archive at this moment

Event by event

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

Hail, Yellowstone

When
August 7, 6:30 PM MST
Where
Yellowstone County, Comanche
Measured
0.88 in hail
Reported by
TRAINED SPOTTER
Coordinates
46.000, -108.770

Spotter report of nickel size hail.

Flash Flood, Golden Valley

When
August 7, 8:30 PM MST to 9:50 PM MST
Where
Golden Valley County, 5 mi E of Lavina
Reported by
TRAINED SPOTTER
Coordinates
46.381, -109.175 (the zone’s center; the record gives no point)

Flash Flood, Musselshell

When
August 7, 8:30 PM MST to 9:50 PM MST
Where
Musselshell County, 12 mi SW of Roundup
Reported by
TRAINED SPOTTER
Coordinates
46.497, -108.398 (the zone’s center; the record gives no point)

Flash Flooding was reported in the coulees draining into the Musselshell River along the border between Golden Valley and Musselshell Counties. Water 2 to 3 feet deep covered roadways and ripped out fences.

What these are

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

More

Every storm in Montana in 1999Every state in 1999This day in weather historyWarnings in Montana, August 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 2026-09-24. Each event’s entry at NCEI: 5710922, 5710923, 5710973.