Flash Flooding in Montana, July 15, 2001

Name: Flash Flooding in Montana, July 15, 2001
Start: 2001-07-15T16:05
End: 2001-07-15T16:05
Location: Montana

July 15, 2001 · NWS MSO · 2 events in 1 county or zone

Strong thunderstorms with heavy rain moved across severely burned areas of southern Ravalli County. Several roads were washed out with some people stranded on North Fork Rye Creek road.

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: 2

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 MSO wrote it up.

Strong thunderstorms with heavy rain moved across severely burned areas of southern Ravalli County. Several roads were washed out with some people stranded on North Fork Rye Creek road. Minor flooding and debris reported on highway 93 near Conner. Spotters reported 0.50 inches of rainfall in one-half hour in the area.

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 Missoula, MT wrote its last area forecast discussion before the first event at Jul 15, 12:54 PM MST, 3 hours 11 minutes earlier.

Area forecast discussion, Jul 15, 12:54 PM MST, 3 hours 11 minutes before

WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
154 PM MDT SUN JUL 15 2001

.SHORT TERM...MODELS CONSISTENT IN DROPPING AN UNSEASONABLY STRONG
UPPER TROUGH INTO WA STATE MONDAY. THIS WILL BRING SIGNIFICANT
COOLING TO THE AREA ON MONDAY. AHEAD OF THE UPPER TROF A STRONG
VORT OVER CENTRAL ID WILL TRACK NE IN SOUTHWESTERLY FLOW ALOFT INTO
SW MT LATER THIS AFTERNOON. AT THE PRESENT TIME AN AREA OF STRONGER
CONVECTION IS DEVELOPING JUST AHEAD OF VORT CENTER IN A DRY SLOT IN
SOUTHEAST IDAHO AND WESTERN LEMHI COUNTIES. OTHER ISOLATED CONVECTION
IS POPPING UP IN SRN HALF OF CWA. LIGHT SHOWERS CONTINUE ALONG
DEFORMATION AXIS INTO NW MT. CONVECTION WILL CONTINUE TO DEVELOP
WITH AFTERNOON HEATING AND SPREAD NE. WITH PRECIP. WATER VALUES OF
GREATER THAN 0.75...BRIEF HEAVY RAIN IS POSSIBLE. STORMS ARE MOVING
FAST ENOUGH THAT SIGNIFICANT PROBLEMS ARE NOT LIKELY. BUT WILL
MONITOR PRECIP TOTAL IN BURN AREAS CLOSELY. CONVECTION WILL DIMINISH
THIS EVENING AS VORT TRACKS NE OF AREA.

ON MONDAY MORNING A DEVELOPING FRONTAL ZONE WILL MOVE SLOWLY EAST
THROUGH CWA FORCING SHOWERS AND POSSIBLY A FEW THUNDERSTORMS AS LI
VALUES REMAIN AROUND 0 TO -1 AS 700 MB COOL TO -2 TO +2 CELCIUS. NGM
MOS IS MUCH WARMER ON THE HIGH TEMPS FOR MONDAY AND TUESDAY THAN THE
MAV MOS. NGM TEMPS ARE CLOSE TO ADIABATIC VALUES...BUT WITH CLOUD
COVER AND SHOWERS WILL TREND BETWEEN THE MOS VALUES...SO MAINLY 60S
NORTH AND 70S SOUTH. TEMPS WILL COOL A LITTLE MORE ON TUESDAY AS
UPPER LOW EDGES SLOWLY EAST. AVN AND MESOETA WRAP A VORT LOBE AROUND
UPPER LOW AS JET STREAK ROUNDS BASE OF TROUGH. DRY MID LEVEL AIR
ADVECTS INTO MOST OF CWA...EXCEPT OVER FAR NW AND SE WHERE WILL
CONTINUE THE BEST CHANCE OF SHOWERS. PETRESCU

.EXTENDED...MODELS IN GOOD AGREEMENT WITH MOVING A TROUGH ACROSS THE
AREA ON WEDNESDAY...COOLING TEMPERATURES AND GIVING THE BEST CHANCE
OF SHOWERS/THUNDERSTORMS. THURSDAY THROUGH SATURDAY A LOW DEVELOPS
AND STAYS OFF THE PACIFIC NORTHWEST COAST...KEEPING THE CWA IN A
SOUTHWEST FLOW WITH A FEW WEAK DISTURBANCES MOVING THROUGH...SO
WILL KEEP A SLIGHT CHANCE OF SHOWERS. BY SUNDAY A WEAK RIDGE BUILDS
OVER THE CWA SO WILL GO DRY AND WARMER. KOLATA

.MSO...NONE.

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

2 flash flood. Local standard time, as filed.

Flash Flood, Ravalli

When: July 15, 4:05 PM MST
Where: Ravalli County, 6 mi SE of Darby
Reported by: LAW ENFORCEMENT
Coordinates: 46.082, -114.121 (the zone’s center; the record gives no point)

Flash Flood, Ravalli

When: July 15, 4:05 PM MST
Where: Ravalli County, Conner
Reported by: LAW ENFORCEMENT
Coordinates: 46.082, -114.121 (the zone’s center; the record gives no point)

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.

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: 5257195, 5257196.