Alert archive / Colorado / Flash Flood Warnings in 1997

Flash Flood Warning 36, NWS Denver/Boulder, CO

July 31, 1997Logan County, Washington County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 31, 1997, 5:30 PM MDT for Logan County, Washington 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 the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued
Jul 31, 1997, 5:30 PM MDT (23:30 UTC)
Expired
Jul 31, 1997, 8:30 PM MDT
In force
3 hr
Issued by
NWS Denver/Boulder, CO
Area
Whole counties; the outline is the Mesonet’s reconstruction

Counties Logan County, CO, Washington County, CO

The radar

The Goodland radar (KGLD), 147 km from the middle of the area, began a volume at 23:33 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

Denver, CO (KDNR), launched 12:00Z, 11.5 hours before the alert went out and 55 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, Denver, CO at 12:00Z on 1997-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 64 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, Denver, CO at 12:00Z on 1997-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 9 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
64 J/kg
Mixed-layer CIN
-197 J/kg
Mixed-layer LCL
1163 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
9 m²/s²
0-3 km storm-relative helicity
34 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDEN 312332
FFWDEN
COC075-121-010230-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
530 PM MDT THU JUL 31 1997

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A FLASH FLOOD
WARNING EFFECTIVE UNTIL 830 PM MDT FOR PEOPLE IN THE FOLLOWING
COUNTIES

IN NORTHEAST COLORADO
     NORTHEASTERN WASHINGTON AND SOUTHEASTERN LOGAN

INCLUDING THE FOLLOWING LOCATIONS
     BURDETT...LONE STAR...OTIS...PLATNER AND ST PETERSBURG

AT 525 PM MDT WEATHER SERVICE DOPPLER RADAR INDICATED TORRENTIAL  
RAINFALL OVER NORTHEASTERN WASHINGTON COUNTY.  THE HEAVIEST RAINFALL 
WAS INDICATED OVER OPEN RANGELAND 6 MILES NORTH OF OTIS ALONG STATE 
HIGHWAY 61.  HIGH WATERS WILL LIKELY DEVELOP ALONG SURVEYOR CREEK IN 
THE VERY NEAR FUTURE.  

RADAR WAS ESTIMATING RAINFALL RATES OF 2 TO 3 INCHES PER HOUR IN THE 
WARNING AREA.  

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...NORMALLY DRY WASHES AND 
ARROYOS...AS WELL AS LOW AREAS ALONG THE BANKS OF 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 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
DENVER.

BAKER
LAT...LON 4045 10281 3991 10281 4000 10317 4042 10320
          4060 10268 T4045 10268

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 31, 2:00 PM MDT, 3 hours 30 minutes before
COZ041-312045-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
200 PM MDT THU JUL 31 1997

...THUNDERSTORMS WITH HEAVY RAIN IN WESTERN ELBERT COUNTY...

AT 155 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
THUNDERSTORMS WITH HEAVY RAIN OVER WESTERN ELBERT COUNTY.  SMALL
HAIL IS ALSO POSSIBLE WITH THE STORMS.

THE STORMS WERE MOVING NORTHEAST AT 20 MILES PER HOUR.

DOPPLER RADAR ESTIMATED UP TO AN INCH AN HOUR HAD FALLEN SOUTHWEST
OF KIOWA.

PERSONS IN OR NEAR ELIZABETH AND KIOWA SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER AND MOVE TO A PLACE OF SAFETY IF BAD WEATHER
APPROACHES.

SOME ROADS MAY BE COVERED WITH WATER.  DO NOT ATTEMPT TO DRIVE
THROUGH WATER OF UNKNOWN DEPTH.

A FLASH FLOOD WATCH IS IN EFFECT FOR MUCH OF NORTHEAST COLORADO
UNTIL MIDNIGHT TONIGHT.

LESZCYNSKI
Special weather statement, Jul 31, 2:03 PM MDT, 3 hours 27 minutes before
COZ041-312045-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
200 PM MDT THU JUL 31 1997

...THUNDERSTORMS WITH HEAVY RAIN IN WESTERN ELBERT COUNTY...

AT 155 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
THUNDERSTORMS WITH HEAVY RAIN OVER WESTERN ELBERT COUNTY.  SMALL
HAIL IS ALSO POSSIBLE WITH THE STORMS.

THE STORMS WERE MOVING NORTHEAST AT 20 MILES PER HOUR.

DOPPLER RADAR ESTIMATED UP TO AN INCH AN HOUR HAD FALLEN SOUTHWEST
OF KIOWA.

PERSONS IN OR NEAR ELIZABETH AND KIOWA SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER AND MOVE TO A PLACE OF SAFETY IF BAD WEATHER
APPROACHES.

SOME ROADS MAY BE COVERED WITH WATER.  DO NOT ATTEMPT TO DRIVE 0
THROUGH WATER OF UNKNOWN DEPTH.

A FLASH FLOOD WATCH IS IN EFFECT FOR MUCH OF NORTHEAST COLORADO
UNTIL MIDNIGHT TONIGHT.

LESZCYNSKI
Special weather statement, Jul 31, 4:04 PM MDT, 1 hour 26 minutes before
COZ040-312245-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
404 PM MDT THU JUL 31 1997

...THUNDERSTORMS PRODUCING HEAVY RAIN IN OVER NORTH CENTRAL
DOUGLAS...WESTERN ARAPAHOE...SOUTHWESTERN DENVER AND SOUTHWESTERN
ADAMS COUNTIES...

AT 405 PM MDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
THUNDERSTORM OVER SOUTH GLENN...OR ABOUT 10 MILES SOUTH OF DENVER.
THIS STORM WAS MOVING NORTHEAST AT 20 MILES PER HOUR AND PRODUCING
RAINFALL AMOUNTS OF UP TO 0.50 INCHES OF RAIN PER HOUR.

PERSONS IN OR NEAR AURORA...SOUTHERN DENVER...ENGLEWOOD...
LITTLETON...ARAPAHOE PARK...CHATFIELD RESERVOIR...GREENWOOD
VILLAGE...HIGHLANDS RANCH AND SHERIDAN SHOULD BE ON THE LOOKOUT FOR
HEAVY RAINFALL.  HEAVY RAINS MAY FLOOD LOW LYING AREAS SUCH AS
DITCHES AND UNDERPASSES. AVOID THESE AREAS AND DO NOT CROSS FLOODED
ROADS AS THEY MAY BE WASHED OUT. WATER LEVELS OF SMALL STREAMS AND
RIVERS MAY ALSO RISE...THEREFORE SEEK HIGHER GROUND IF THREATENED BY
FLOOD WATERS.

SHORT LIVED WEAK TORNADOES ARE ALSO POSSIBLE WITH THIS STORM.

RJK

The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 30, 6:35 PM MDTFlash Flood WarningBOULogan, Weld3 hr
Jul 30, 8:05 PM MDTFlash Flood WarningBOUArapahoe, Denver115 min
Jul 31, 2:25 PM MDTSevere Thunderstorm WarningBOUElbert35 min
Jul 31, 3:28 PM MDTTornado WarningBOUElbert32 min
Jul 31, 4:00 PM MDTSevere Thunderstorm WarningBOULincoln, Washington60 min
Jul 31, 4:00 PM MDTSevere Thunderstorm WarningBOUElbert60 min
Jul 31, 5:27 PM MDTFlash Flood WarningBOUMorgan2 hr
Jul 31, 5:30 PM MDTFlash Flood WarningBOUDouglas2 hr

Nearby

Flash Flood Warnings in Colorado, 1997Every flash flood warning in 1997

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.