Alert archive / Montana / Flash Flood Warnings in 2002

Flash Flood Warning 3, NWS Great Falls, MT

August 21, 2002Lewis and Clark County, Montana

NWS Great Falls, MT issued this flash flood warning at Aug 21, 2002, 8:05 PM MDT for Lewis and Clark County, Montana. It was in force for 115 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 21, 2002, 8:05 PM MDT (02:05 UTC)
Expired
Aug 21, 2002, 10:00 PM MDT
In force
115 min
Issued by
NWS Great Falls, MT
Area
Counties, with a storm outline in the text

County Lewis and Clark County, MT

The radar

The Great Falls radar (KTFX), 80 km from the middle of the area, began a volume at 02:04 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Great_falls, MT (KTFX), launched 00:00Z, 2.1 hours before the alert went out and 119 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Great_falls, MT at 00:00Z on 2002-08-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 280 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Great_falls, MT at 00:00Z on 2002-08-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 13 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
280 J/kg
Mixed-layer CIN
-17 J/kg
Mixed-layer LCL
1156 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
13 m²/s²
0-3 km storm-relative helicity
2 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WGUS55 KTFX 220205
FFWTFX
MTC049-220400-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
804 PM MDT WED AUG 21 2002

THE NATIONAL WEATHER SERVICE IN GREAT FALLS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CAVE GULCH BURN AREA ON THE NORTHEAST END OF CANYON FERRY RESERVOIR

* UNTIL 1000 PM MDT

* AT 800 PM MDT...WEATHER SERVICE RADAR INDICATED VERY HEAVY RAIN 
OVER EXTREME SOUTHEASTERN LEWIS AND CLARK COUNTY...OR ABOUT 17   
MILES NORTHEAST OF HELENA.

THE HEAVY RAIN IS FALLING OVER THE CAVE GULCH BURN AREA ON THE 
NORTHEAST SIDE OF CANYON FERRY RESERVOIR. THIS AREA IS SUBJECT TO 
DEBRIS FLOWS AND FLASH FLOODS DURING PERIODS OF HEAVY RAIN. 

A FLASH FLOOD WARNING MEANS THAT FLOODING OR DEBRIS FLOWS ARE 
IMMINENT OR OCCURRING. IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER 
GROUND IMMEDIATELY. RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD 
TAKE IMMEDIATE PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT 
ATTEMPT TO CROSS SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH 
BY FOOT OR BY AUTOMOBILE. IF YOUR VEHICLE STALLS, ABANDON IT 
IMMEDIATELY AND SEEK HIGHER GROUND.

TO REPORT SEVERE WEATHER HAVE THE NEAREST LAW ENFORCEMENT AGENCY
RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN
GREAT FALLS.

LAT...LON 4674 11191 4681 11169 4696 11192

The office that day

Everything else NWS Great Falls, MT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 21, 7:44 PM MDTSevere Thunderstorm WarningTFXBroadwater31 min
Aug 21, 8:25 PM MDTSevere Thunderstorm WarningTFXBroadwater, Meagher35 min
Aug 22, 4:46 PM MDTSevere Thunderstorm WarningTFXJudith Basin59 min
Aug 22, 5:10 PM MDTSevere Thunderstorm WarningTFXFergus65 min

Nearby

Flash Flood Warnings in Montana, 2002Every flash flood warning in 2002

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.