Alert archive / Montana / Flash Flood Warnings in 1987

Flash Flood Warning 1, NWS Great Falls, MT

July 29, 1987Chouteau County, Teton County, Montana

NWS Great Falls, MT issued this flash flood warning at Jul 29, 1987, 7:33 PM MDT for Chouteau County, Teton County, Montana. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Jul 29, 1987, 7:33 PM MDT (01:33 UTC)
Expired
Jul 29, 1987, 10:30 PM MDT
In force
3 hr
Issued by
NWS Great Falls, MT
Area
Whole counties

Counties Chouteau County, MT, Teton County, MT

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

The nearest sounding before it

Great Falls, MT (KGTF), launched 00:00Z, 1.6 hours before the alert went out and 42 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 1987-07-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 195 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Great Falls, MT at 00:00Z on 1987-07-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 84 square meters per square second.19395878Sfc1 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
195 J/kg
Mixed-layer CIN
-125 J/kg
Mixed-layer LCL
1615 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
84 m²/s²
0-3 km storm-relative helicity
137 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 
TTAA00 KGTF 300133
FFWGTF
MTC015-099-300430-
 
BULLETIN - EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE GREAT FALLS MT
733 PM MDT WED JUL 29 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING
EFFECTIVE UNTIL 1030 PM MDT FOR PEOPLE IN THE FOLLOWING COUNTIES...
 
IN NORTHWEST MONTANA
          ...WESTERN CHOUTEAU...EASTERN TETON
 
DISASTER AND EMERGENCY SERVICES OFFICIAL REPORTS 2 1/2 INCHES OF RAIN
RECEIVED EARLIER THIS EVENING ABOUT 7 MILES EAST OF CHOTEAU CAUSING
FLOODING OF THE TETON RIVER WITH WATER OVER THE ROAD AT COLLINS. THIS
WATER WILL BE MOVING DOWNSTREAM ON THE TETON TONIGHT AND ANY FURTHER
THUNDERSTORM ACTIVITY IN THE AREA COULD CAUSE FURTHER FLOODING.
 
 
DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY.  THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO
CROSS SAFELY.  VEHICLES CAUGHT IN RISING WATER SHOULD BE
ABANDONED QUICKLY.  MOVE TO HIGHER GROUND.
 
A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS
IMMINENT.  MOST FLASH FLOOD DEATHS OCCUR IN AUTOMOBILES.  DO NOT
ATTEMPT TO CROSS BRIDGES...DIPS...OR LOW SPOTS IF WATER COVERS
THE ROADWAY.  NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL
ONE...ON FOOT.  TO ESCAPE RISING WATER MOVE UP TO HIGHER GROUND.

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, Jul 29, 1:51 PM MDT, 5 hours 42 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HAVRE MT
155 PM MDT WED JUL 29 1987

...HEAVY THUNDERSTORMS AGAIN FORECAST FOR NORTH-CENTRAL MONTANA...

THUNDERSTORMS..SOME WITH HEAVY RAIN...ARE ONCE AGAIN FORECAST FOR
NORTH-CENTRAL MONTANA FOR LATE THIS AFTERNOON AND EVENING.
THESE STORMS ARE BEING FED BY SUB TROPICAL MOISTURE EXTENDING FROM
MEXICO TO SOUTHERN ALBERTA.

HEAVY RAINFALL FROM STORMS OF THE PAST FEW DAYS HAS LEFT THE SOIL IN
SOME AREAS OF NORTHERN MONTANA SATURATED.  ADDITIONALLY..HIGH
HUMMIDITES HAS RETARDED EVAPORATION.

HEAVY RAIN FALLING OVER THE SATURATED GROUND TONIGHT COULD CAUSE SOME
LOCAL FLOODING IN THIS AREA.

PERSONS SHOULD BE AWARE OF THE CURRENT AND EXPECTED WEATHER CONDI-
TIONS AND LISTEN FOR ANY UPDATED FORECASTS AND STATEMENTS FROM THE
NATIONAL WEATHER SERVICE.
/CORP/
Special weather statement, Jul 29, 5:15 PM MDT, 2 hours 18 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS, MT
506 PM MDT WED JUL 29 1987

...FLASH FLOOD WATCH ISSUED FOR PORTIONS OF NORTHEAST MONTANA THIS
EVENING...

A FLASH FLOOD WATCH HAS BEEN ISSUED FOR PORTIONS OF NORTHEAST MONTANA
THIS EVENING UNTIL 9 PM MDT FOR THE FOLLOWING COUNTIES:
   EASTERN GARFIELD...MCCONE...WESTERN DAWSON...WESTERN RICHLAND AND
   ROOSEVELT...
INCLUDING THE TOWNS OF: BROCKWAY...CIRCLE...BLOOMFIELD...WOLFPOINT
    AND POPLAR

AT 5 PM MDT RADAR INDICATED POSSIBLE HEAVY THUNDERSTORMS NEAR THE
BORDER OF GARFIELD AND MCCONE COUNTIES. ALSO OTHER THUNDERSTORMS WERE
OVER EASTERN MCCONE COUNTY. THESE STORMS WERE MOVING SLOWLY
NORTHEASTWARD AND CARRIED POTENTIA#LLY HEAVY RAIN.

PEOPLE IN THESE COUNTIES SHOULD BE PREPARED TO MOVE TO HIGHER GROUND
IF HEAVY RAIN OCCURS DUE TO THE FLASH FLOOD POTENTIAL.
HALBERT
Special weather statement, Jul 29, 7:27 PM MDT, 6 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HAVRE MT
730 PM MDT WED JUL 29 1987

...FLASH FLOOD WATCH IN EFFECT FOR THE BEAR PAW MOUNTAINS...

A FLASH FLOOD WATCH CONTINUES IN EFFECT UNTIL 2AM THURSDAY MORNING
FOR THE BEAR PAW MOUNTAINS AND SURROUNDING AREAS.

SLOW MOVING THUNDERSTORMS ARE CURRENTLY MOVING VERY SLOWLY ACROSS
THE BEAR PAW MOUNTAINS IN NORTH CENTRAL MONTANA. HEAVY RAIN AND
FREQUENT LIGHTNING CAN BE EXPECTED WITH THESE THUNDERSTORMS.

HEAVY RAINFALL FROM STORMS OF THE PAST FEW DAYS HAS LEFT THE SOIL IN
SOME AREAS OF NORTHERN MONTANA SATURATED.  ADDITIONALLY..HIGH
HUMMIDITES HAS RETARDED EVAPORATION.

A FLASH FLOOD WATCH MEANS FLOODING IS POSSIBLE WITHIN THE WATCH AREA.
PERSONS IN THE WATCH AREA ARE ADVISED TO KEEP INFORMED AND TO BE
READY FOR QUICK ACTION IF FLASH FLOODING IS OBSERVED OR IF A WARNING
IS ISSUED.
/CHAMBERLAIN/

Nearby

Flash Flood Warnings in Montana, 1987Every flash flood warning in 1987

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.