Flash Flood and Hail in Montana, August 29, 2002

Name: Flash Flood and Hail in Montana, August 29, 2002
Start: 2002-08-29T16:20
End: 2002-08-29T19:51
Location: Montana

August 29, 2002 · NWS BYZ · 3 events in 2 counties and zones

1 thunderstorm wind, 1 hail, 1 flash flood, 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

Open the live radar over this ground

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.

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 Aug 29, 1:13 PM MST, 3 hours 7 minutes earlier.

Area forecast discussion, Aug 29, 1:13 PM MST, 3 hours 7 minutes before

SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
213 PM MDT THU AUG 29 2002

.SHORT TERM...VALID FOR FRI AND SAT...
FORECAST PROBLEM WILL BE TIMING AND EXTENT OF CONVECTION OVER THE NEXT
COUPLE OF DAYS. AVN AND ETA HANDLING OVERALL PATTERN WELL EXCEPT FOR
TIMING AND STRENGTH OF WAVES.

TONIGHT AND FRIDAY...UPPER TROUGH SWINGS ACROSS MONTANA TONIGHT
RESULTING IN CHANCE OF SHOWERS AND THUNDERSTORMS SPREADING FROM WEST
TO EAST ACROSS THE CWA. A FEW ISOLATED SEVERE STORMS POSSIBLE THIS
EVENING GIVEN MODEST CAPE...INVERTED V SIGNATURE ON MODEL SOUNDINGS AND
LOW WET BULB ZERO HEIGHTS. HOWEVER...SHEAR APPEARS TOO WEAK FOR ANY
WIDESPREAD ACTIVITY AND WILL NOT MENTION SEVERE IN FORECAST. PRECIP WILL
LINGER THROUGH MIDDAY IN EAST AS TROUGH AXIS SWINGS OUT OF THE STATE.
TEMPS SHOULD WARM FRIDAY WITH WESTERLY FLOW...BUT SHOULD STILL BE A
FEW DEGREES COOLER THAN TODAY IN WAKE OF TROUGH. NEXT WAVE APPROACHES
WESTERN CWA BY LATE AFTERNOON AHEAD OF NEXT TROUGH AND WILL INTRODUCE
SLIGHT CHANCE IN WEST FOR LATE TOMORROW AFTERNOON.

SATURDAY NIGHT AND SUNDAY...AFOREMENTIONED WAVE WILL BRING SLIGHT CHANCE
OF ACTIVITY TO WESTERN ZONES...AND WILL LEAVE REST OF CWA DRY. SATURDAY
NEXT UPPER TROUGH SWINGS THROUGH MONTANA BRINGING A CHANCE OF PRECIP
TO THE WEST IN THE AFTERNOON AND SPREADING EAST OVERNIGHT. TEMPS
SATURDAY SHOULD BE COOLER THAN FRIDAY WITH INCREASING CLOUD COVER AND
DECREASING MID LEVEL TEMPS DUE TO UPPER TROUGH.

.LONG TERM...VALID FOR SUN...MON...TUE...WED...THU...
WEAKENING UPPER TROUGH TO SLIDE THROUGH EASTERN MONTANA SUNDAY. THIS
WILL SET UP DOWNSLOPE FLOW FOR THE FORECAST AREA. LOWER TO MID LEVELS
DRY OUT AS THE TROUGH SWINGS THROUGH WITH A COLD FRONT MOVING ACROSS.
WILL OPT TO LEAVE POPS OUT AS ATMOSPHERE PROGGED TO BE PRETTY DRY.
ATMOSPHERE STABILIZES BEHIND THE FRONT AS WELL.

MODELS IN PRETTY GOOD AGREEMENT IN THE MONDAY THROUGH THURSDAY TIME
FRAME. DRY NORTHWEST FLOW MONDAY GIVES WAY TO SOUTHWEST FLOW TUESDAY
THROUGH THURSDAY. SHOULD SEE WARMER TEMPERATURES TUESDAY AND WEDNESDAY
WITH DOWNSLOPE AHEAD OF COLD FRONT PROGGED FOR WEDNESDAY AFTERNOON AND
NIGHT. WILL INTRODUCE A CHANCE OF THUNDERSTORMS WEDNESDAY AFTERNOON AND
NIGHT. WILL LEAVE THURSDAY DRY...EVEN THOUGH SOUTHWEST FLOW PERSISTS.
WAVES APPEAR FARTHER NORTH THURSDAY AND THE FRONTAL BOUNDARY WILL BE
WELL SOUTH FOR LITTLE TO NONE SURFACE CONVERGENCE. GOING TEMPERATURES
LOOK GOOD AND WILL LET RIDE. HUMPHREY

    FRI     SAT     SUN     MON     TUE     WED     THU
-----------------------------------------------------------
BIL 058/084 056/080 054/081 053/073 054/077 054/078 056/077
    40/B    03/T    30/B    00/B    00/B    03/T    30/B
LVM 046/078 046/075 046/078 047/072 045/074 046/074 048/073
    42/T    23/T    20/B    00/B    00/B    03/T    30/B
HDN 058/086 054/081 053/083 049/075 055/079 055/080 058/079
    40/B    03/T    30/B    00/B    00/B    03/T    30/B
MLS 062/088 061/082 057/083 054/074 056/080 056/081 059/080
    42/T    02/T    30/B    00/B    00/B    03/T    30/B
4BQ 060/088 059/083 055/084 053/073 054/081 055/081 058/080
    42/T    02/T    30/B    00/B    00/B    03/T    30/B
BHK 060/087 060/081 055/082 051/070 055/078 055/080 058/079
    42/T    00/B    30/B    00/B    00/B    03/T    30/B
SHR 053/085 054/084 051/082 051/070 051/081 052/082 056/081
    40/B    03/T    30/B    00/B    00/B    03/T    30/B

.BYZ...
MT...NONE.
WY...NONE.

The radar

The Billings radar (KBLX), 11 km away, was scanning. The volume nearest the first event began at 23:21 UTC.

Open the radar archive at this moment

Event by event

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

Thunderstorm Wind, Yellowstone

When: August 29, 4:20 PM MST
Where: Yellowstone County, Billings
Measured: 60 kt (69 mph)
Reported by: TRAINED SPOTTER
Coordinates: 45.800, -108.483

Hail, Treasure

When: August 29, 5:10 PM MST
Where: Treasure County, 10 mi NW of Hysham
Measured: 1 in hail
Reported by: TRAINED SPOTTER
Coordinates: 46.400, -107.367

Flash Flood, Treasure

When: August 29, 7:51 PM MST
Where: Treasure County, 15 mi SW of Hysham
Reported by: TRAINED SPOTTER
Coordinates: 46.212, -107.272 (the zone’s center; the record gives no point)

Pease Bottom Road under water. Nearby fields flooded.

What these are

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.
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

Every storm in Montana in 2002 Every state in 2002 This day in weather history Warnings in Montana, August 2002

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: 5315065, 5315066, 5315067.