Alert archive / Colorado / Flash Flood Warnings in 1991

Flash Flood Warning 7, NWS Denver/Boulder, CO

August 18, 1991Clear Creek County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Aug 18, 1991, 10:19 PM MDT for Clear Creek County, Colorado. It was in force for 86 min.

The area

The counties it named.

The facts

Issued: Aug 18, 1991, 10:19 PM MDT (04:19 UTC)
Expired: Aug 18, 1991, 11:45 PM MDT
In force: 86 min
Issued by: NWS Denver/Boulder, CO
Area: Whole counties

County Clear Creek County, CO

The nearest sounding before it

Denver, CO (KDEN), launched 00:00Z, 4.3 hours before the alert went out and 207 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 344 J/kg
Mixed-layer CIN: -8 J/kg
Mixed-layer LCL: 2106 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: -23 m²/s²
0-3 km storm-relative helicity: 95 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.

000 
TTAA00 KDEN 190427
FFWDEN
COC019-190545-

BULLETIN - EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
1019 PM MDT SUN AUG 18 1991

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A FLASH FLOOD
WARNING EFFECTIVE UNTIL MIDNIGHT FOR PEOPLE IN THE FOLLOWING
COUNTY

IN CENTRAL COLORADO
     NORTHERN AND CENTRAL CLEAR CREEK

INCLUDING THE FOLLOWING TOWNS
     IDAHO SPRINGS AND DUMONT

AT 1019 PM MDT RADAR INDICATED HEAVY RAIN ALONG THE CONTINENTAL DIVIDE
NEAR BERTHOUD PASS...SIX MILES NORTHWEST OF SILVER PLUME ...OR ABOUT 47
MILES WEST OF DENVER.

SANDBAGGING WAS CONTINUING IN PARTS OF IDAHO SPRINGS AS CLEAR CREEK IS
ABOUT 2 FEET OUT OF ITS BANKS.  

IF YOU LIVE IN VIRGINIA CANYON...YORK GULCH...OR ALONG FALL
RIVER...EXPECT RISING WATER.  EXCESSIVE RUNOFF FROM THIS STORM WILL
CAUSE FLASH FLOODING OF
SMALL CREEKS AND STREAMS.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS 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.  DO NOT ATTEMPT TO CROSS SWIFTLY
FLOWING WATERS BY FOOT OR BY AUTO.  DO NOT ATTEMPT TO DRIVE
OVER A ROAD COVERED BY WATER.  THE ROAD COULD BE WASHED OUT
UNDER THE WATER SURFACE.

TO REPORT FLOODING HAVE THE NEAREST LAW ENFORCEMENT
AGENCY RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE
FORECAST OFFICE IN DENVER.

RUFF
LAT...LON 3961 10546 3966 10572 3978 10581 3975 10547

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, Aug 18, 6:43 PM MDT, 3 hours 36 minutes before

COZ011-190115-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
640 PM MDT SUN AUG 18 1991

...THUNDERSTORMS OVER SOUTHERN METRO AREA AND ARAPAHOE COUNTY...

AT 635 PM...NATIONAL WEATHER SERVICE RADAR INDICATED A STRONG
THUNDERSTORM WAS LOCATED IN CENTRAL ARAPAHOE COUNTY WITH ANOTHER
THUNDERSTORM DEVELOPING OVER LAKEWOOD AND SOUTHERN DENVER.  THE STORM IN
CENTRAL ARAPAHOE COUNTY WAS LOCATED ABOUT 12 MILES SOUTH-SOUTHWEST OF
BYERS.  BOTH STORMS WERE MOVING EASTWARD AT ABOUT 15 MILES AN HOUR.

THESE STORMS COULD PRODUCE BRIEF HEAVY RAIN...GUSTY WINDS...FREQUENT
LIGHTNING AND POSSIBLY SOME HAIL.  THE ARAPAHOE COUNTY STORM SHOULD
CROSS INTERSTATE 70 NEAR DEER TRAIL IN THE NEXT HALF HOUR.  MOTORISTS
SHOULD BE PREPARED FOR LOW VISIBILITIES AND WATER ON ROAD SURFACES.
PARTS OF SOUTHERN DENVER COULD ALSO EXPERIENCE SOME STREET FLOODING AS
THE LAKEWOOD THUNDERSTORM MOVES OVERHEAD.  MOTORISTS SHOULD NOT TRY TO
CROSS STREETS COVERED BY WATER.

STAY TUNED TO NOAA WEATHER RADIO FOR LATER STATEMENTS.

DANKERS

Nearby

Flash Flood Warnings in Colorado, 1991 Every flash flood warning in 1991

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.