Flash Flood in Idaho, June 22, 2002

Name: Flash Flood in Idaho, June 22, 2002
Start: 2002-06-22T18:00
End: 2002-06-22T19:00
Location: Idaho

June 22, 2002 · NWS MSO · 1 event in 1 county or zone

A slow moving thunderstorm dropped heavy rain south of Lolo Pass, near the town of Powell. A damage survey reported a culvert wash out and evidence of overland flooding.

Where it happened

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The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 1

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.

A slow moving thunderstorm dropped heavy rain south of Lolo Pass, near the town of Powell. A damage survey reported a culvert wash out and evidence of overland flooding. Rainfall estimates were over 2 inches with this storm.

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 Jun 22, 1:46 PM MST, 4 hours 14 minutes earlier.

Area forecast discussion, Jun 22, 1:46 PM MST, 4 hours 14 minutes before

WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
246 PM MDT SAT JUN 22 2002

.SHORT TERM...BREAKS IN THE CLOUDS AND THE INTRUSION OF THE UPPER
WAVE HAS RESULTED BETTER DESTABILIZATION ACROSS THE CWA. THUS...
SHOWERS AND THUNDERSTORMS HAVE DEVELOPED. THESE STORMS WERE MAINLY
IN THE MOST UNSTABLE AIR ACROSS THE SOUTHEAST CWA ALONG WITH STEEPER
LAPSE RATES. THE STORMS ARE SLOW MOVING WITH A WEAK WIND FIELD
ALOFT...THEREFORE SOME OF THE STRONGER CELLS MAY PRODUCE SOME HEAVY
RAIN. A FLASH FLOOD WATCH HAS BEEN ISSUED FOR THE BURNED AREAS OF
RAVALLI COUNTY...WHERE THE STORMS HAVE DEVELOPED AND WERE
SUBSEQUENTLY APPROACHING AT A SLOW RATE. MOST OF THIS ACTIVITY WILL
DIMINISH AFTER SUNSET WITH THE EXCEPTION OF THE FAR EASTERN CWA WHERE
SOME WRAP-AROUND SHOWERS MAY CONTINUE UNTIL THE LATE HOURS TONIGHT.
BY TOMORROW...THE UPPER TROUGH WILL BE EAST OF THE AREA AND WE WILL
RETURN TO A RESIDUAL MID LEVEL MOISTURE REGIME WITH BUILDING
HEIGHTS. MORE STABLE AIR WITH SOME RESIDUAL DECENT THETA-E AIR ONLY
ALONG THE SOUTHERNMOST CWA. THEREFORE...ISOLATED SHOWERS WITH SOME
THUNDER MIXED IN IN THE SOUTHERN HALF OF THE CWA. DRIER AIR WILL
CONTINUE TO MOVE IN AS HEIGHTS BUILD FURTHER MONDAY THROUGH
TUESDAY. THERE WILL REMAIN A SLIGHT CHANCE FOR ISOLATED ACTIVITY IN
THE SOUTHERN CWA AND IDAHO...BUT ANY DEVELOPMENT WILL LIKELY BE
HIGH BASED UNDER THIS DRYING AIR MASS. SHOULD ALSO SEE A RISE IN
TEMPS THROUGH THE SHORT TERM...POSSIBLY HITTING 90S IN THE WARMER
LOCATION OF WESTERN MONTANA...AND CERTAINLY IN THE NORTH CENTRAL
IDAHO ZONES.   DICKSON

.LONG TERM...THE CANADIAN...MRF/AVN...AND UKMET MODELS ALL SHOW A
LARGE HIGH AMPLITUDE RIDGE BUILDING IN OVER THE AREA THROUGH THE
PERIOD. AS IT DOES SO THE AREA GETS PLACED IN UPPER LEVEL SOUTHWEST
FLOW WEDNESDAY AND THURSDAY. WEAK WAVES IN THE FLOW WILL MAKE THE
ATMOSPHERE UNSTABLE IN THE SOUTHERN PORTIONS OF THE CWA WITH LIFTED
INDICES APPROACHING -7 AND LAPSE RATES OF 8.5 DEG C/KM. THIS SHOULD
MAKE FOR A SLIGHT CHANCE OF AFTERNOON/EVENING SHOWERS AND
THUNDERSTORMS. FRIDAY AND SATURDAY SHOULD BE DRY AS THE RIDGE BUILDS
IN. TEMPERATURES WILL START OUT HOT AND CONTINUE TO RISE THROUGH THE
PERIOD. GILCHRIST

.MSO...FLASH FLOOD WATCH FOR THE BURNED AREAS OF RAVALLI COUNTY IN
       THE BITTERROOT TIL 04Z.

...7-DAY SPOT TEMPS AND POPS...
LIB EBB 054/083 051/086 051/090 37211000
     UUUU 050/088 051/089 051/090 051/090 3300000000
FCA EBU 051/079 047/081 048/085 37411000
     UUUU 048/086 050/087 050/088 050/088 3300000000
POL EBU 057/079 052/081 051/085 37411000
     UUUU 049/087 050/088 050/089 050/089 3300000000
MSO EBU 053/080 050/084 050/088 37511011
     UBUU 051/089 053/090 053/091 053/091 3300110000
HMM EBU 054/081 051/085 050/089 37611111
     UBUU 053/090 055/091 054/092 054/092 3300110000
BTM EBB 048/076 046/080 045/083 37622121
     BBUU 046/085 047/086 048/087 049/087 3311110000
ORO BBB 057/085 056/087 054/092 37211011
     UUUU 056/093 055/094 056/095 056/095 3300000000
GRV BBB 055/081 054/084 050/088 37211011
     UUUU 055/090 054/091 055/092 055/092 3300000000
SMN BBB 052/080 050/083 050/086 37522121
     BBUU 051/089 053/090 053/091 053/091 3311110000

The radar

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

Open the radar archive at this moment

Event by event

1 flash flood. Local standard time, as filed.

Flash Flood, Idaho

When: June 22, 6:00 PM MST to 7:00 PM MST
Where: Idaho County, East Central Portion
Reported by: GENERAL PUBLIC
Coordinates: 45.844, -115.467 (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 Idaho in 2002 Every state in 2002 This day in weather history Warnings in Idaho, June 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: 5300302.