Flash Flood and Hail in Montana, July 14, 1999

Name: Flash Flood and Hail in Montana, July 14, 1999
Start: 1999-07-14T17:00
End: 1999-07-14T19:50
Location: Montana

July 14, 1999 · NWS BYZ · 5 events in 2 counties and zones

3 thunderstorm wind, 1 flash flood, 1 hail, as filed by the National Weather Service.

Where it happened

Every event with a place to put it; 1 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: 5

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), 151 km away, was scanning. The volume nearest the first event began at 00:25 UTC.

Open the radar archive at this moment

Event by event

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

Flash Flood, Rosebud

When: July 14, 5:00 PM MST to 7:50 PM MST
Where: Rosebud County, Vananda
Reported by: LAW ENFORCEMENT
Coordinates: 46.230, -106.731 (the zone’s center; the record gives no point)

Two inches of rain fell in less than one hour just south of Vananda as a slow moving thunderstorm moved over the area. The water was up to a foot deep.

Hail, Rosebud

When: July 14, 5:27 PM MST to 5:33 PM MST
Where: Rosebud County, Forsyth to 14 mi W of Forsyth
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 46.270, -106.970

Dime size hail was reported by two spotters west of Forsyth.

Thunderstorm Wind, Rosebud

When: July 14, 5:30 PM MST to 5:40 PM MST
Where: Rosebud County, Forsyth to 10 mi of Forsyth
Measured: 80 kt (92 mph)
Reported by: TRAINED SPOTTER
Coordinates: 46.270, -106.880

Wind gusts as high as 92 mph were reported 7 miles west of Forsyth. Three buildings were destroyed 10 miles west of Forsyth and several tree branches were broken in the Forsyth area. Widespread power outages were reported near Forsyth. Corn and beet crops sustained heavy losses.

Thunderstorm Wind, Rosebud

When: July 14, 6:45 PM MST to 7:45 PM MST
Where: Rosebud County, Hathaway
Measured: 52 kt (60 mph)
Reported by: TRAINED SPOTTER
Coordinates: 46.270, -106.200

Spotter estimated 60 mph wind gust.

Thunderstorm Wind, Custer

When: July 14, 7:00 PM MST
Where: Custer County, Miles City
Measured: 52 kt (60 mph)
Reported by: TRAINED SPOTTER
Coordinates: 46.400, -105.830

Spotter estimated 60 mph wind gust.

What these are

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.
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.

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

The same day elsewhere

Every storm in Montana in 1999 Every state in 1999 This day in weather history Warnings 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: 5708538, 5708537, 5708536, 5708539, 5708540.