Alert archive / Colorado / Flash Flood Warnings in 2002

Flash Flood Warning 21, NWS Grand Junction, CO

August 3, 2002La Plata County, Colorado

NWS Grand Junction, CO issued this flash flood warning at Aug 3, 2002, 1:37 PM MDT for La Plata County, Colorado. It was in force for 3 hr. 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 3, 2002, 1:37 PM MDT (19:37 UTC)
Expired
Aug 3, 2002, 4:30 PM MDT
In force
3 hr
Issued by
NWS Grand Junction, CO
Area
Counties, with a storm outline in the text

County La Plata County, CO

The radar

The Grand Junction radar (KGJX), 185 km from the middle of the area, began a volume at 19:40 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

Grand Junction, CO (KGJT), launched 12:00Z, 7.6 hours before the alert went out and 199 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, Grand Junction, CO at 12:00Z on 2002-08-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 371 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, Grand Junction, CO at 12:00Z on 2002-08-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 13 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
371 J/kg
Mixed-layer CIN
-25 J/kg
Mixed-layer LCL
971 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
13 m²/s²
0-3 km storm-relative helicity
32 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

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

779 
WGUS55 KGJT 031937
FFWGJT
COC067-032230-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
135 PM MDT SAT AUG 3 2002

THE NATIONAL WEATHER SERVICE IN GRAND JUNCTION HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHEAST LA PLATA COUNTY IN SOUTHWEST COLORADO

* UNTIL 430 PM MDT

* AT 135 PM MDT...STRONG THUNDERSTORMS WITH HEAVY RAIN CONTINUE TO
  DEVELOP AROUND THE MISSIONARY RIDGE BURN AREA.

* THE THUNDERSTORMS WITH EXCESSIVE RAINFALL WILL BE OVER...
  LEMON RESERVOIR BY 200 PM MDT
  VALLECITO RESERVOIR BY 230 PM MDT

THE THUNDERSTORMS ARE MOVING SOUTHWEST TO NORTHEAST AT 20 MPH. 
EXCESSIVE RUNOFF FROM THE HEAVY RAIN WILL CAUSE FLASH FLOODING OF 
CREEKS AND STREAMS...ROADS AND ROADSIDE CULVERTS. THE HEAVY RAINS 
COULD ALSO TRIGGER ROCK AND MUDSLIDES IN STEEP TERRAIN.

HEAVY RAIN OVER THE MISSIONARY RIDGE BURN AREA WILL CAUSE DEBRIS AND 
MUD FLOWS. LA PLATA COUNTY SHERIFF REPORTED 5 FOOT DEEP MUDSLIDES 
EARLIER THIS AFTERNOON ALONG JACK CREEK AND COUNTY ROAD 501. 
RESIDENTS AND MOTORISTS AROUND THIS AREA SHOULD BE PREPARED FOR 
ADDITIONAL FLOODING THROUGHOUT THE AFTERNOON.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY. 

LAT...LON 3738 10783 3734 10767 3732 10748 3762 10749
          3763 10779 3748 10780

DJN



$$
1 follow-up statement
811 
RWUS32 KGJT 032203
FFSGJT
COC067-032230-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
400 PM MDT SAT AUG 3 2002

...THE FLASH FLOOD WARNING WHICH WAS IN EFFECT UNTIL 430 PM MDT FOR
NORTHEASTERN LA PLATA COUNTY HAS BEEN CANCELED...

THE HEAVY RAIN HAS ENDED OVER THE WARNED AREA. STORMS HAVE MOVED OFF 
TO THE NORTHEAST.  AT 330 PM MDT...LOCAL LAW ENFORCEMENT REPORTED 
THE WEST SIDE OF VALLECITO RESERVOIR WAS DEVASTATED WITH DEBRIS 
FLOWS ACROSS FOREST ROAD 501 AND INTO SEVERAL HOMES AND BUSINESSES.

ANY FURTHER MEASURABLE RAINFALL THIS EVENING COULD CAUSE FURTHER 
DEBRIS FLOWS. MOST THUNDERSTORM ACTIVITY IS EXPECTED TO END AFTER 
SUNSET. STAY TUNED TO YOUR FAVORITE MEDIA OUTLET ON THIS SITUATION. 
YOU CAN ALSO GET THE LATEST WARNINGS...FORECASTS...AND STATEMENTS BY 
VISITING THE HOME PAGE OF THE NATIONAL WEATHER SERVICE IN GRAND 
JUNCTION AT WWW.CRH.NOAA.GOV/GJT/

Nearby

Flash Flood Warnings in Colorado, 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.