Alert archive / Colorado / Flash Flood Warnings in 1997

Flash Flood Warning 42, NWS Denver/Boulder, CO

August 5, 1997Larimer County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Aug 5, 1997, 9:12 PM MDT for Larimer County, Colorado. It was in force for 108 min. 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
Aug 5, 1997, 9:12 PM MDT (03:12 UTC)
Expired
Aug 5, 1997, 11:00 PM MDT
In force
108 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties; the outline is the Mesonet’s reconstruction

County Larimer County, CO

The radar

The Cheyenne radar (KCYS), 69 km from the middle of the area, began a volume at 03:14 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 00:00Z, 3.2 hours before the alert went out and 189 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 00:00Z on 1997-08-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 253 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, Denver, CO at 00:00Z on 1997-08-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -22 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
253 J/kg
Mixed-layer CIN
-18 J/kg
Mixed-layer LCL
838 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
-22 m²/s²
0-3 km storm-relative helicity
51 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 060314
FFWDEN
COC069-060500-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
912 PM MDT TUE AUG 5 1997

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A FLASH FLOOD
WARNING EFFECTIVE UNTIL 1100 PM MDT FOR PEOPLE IN THE FOLLOWING
COUNTIES

IN NORTH CENTRAL COLORADO
     CENTRAL LARIMER

INCLUDING THE FOLLOWING LOCATIONS
     FORT COLLINS...BELLVUE...BUCKHORN MOUNTAIN...HARMONY...
     LIVERMORE...MASONVILLE...MISHOWAKA...PINGREE PARK...POUDRE PARK
     AND TEDS PLACE

AT 910 PM MDT WEATHER SERVICE DOPPLER RADAR INDICATED MODERATE TO 
HEAVY RAIN CONTINUING IN AND AROUND THE FORT COLLINS AREA.  THE FORT 
COLLINS POLICE INDICATED SOME STREET FLOODING IN THE WESTERN AND 
DOWNTOWN FORT COLLINS AS WELL AS AROUND THE CSU CAMPUS.  SOME 
STREET FLOODING WAS REPORTED AT STURAT STREET AND COLLEGE AVENUE IN 
THE VICINITY OF SPRING CREEK.  CONSIDERING THE ABUNDANCE OF THE 
CURRENT RAINFALL OVER THE LAST SEVERAL DAYS...EVEN ONE INCH OF RAIN 
WILL CAUSE FLOODING.

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF SMALL 
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES.  
ADDITIONALLY...COUNTRY ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS 
AND STREAMS AND OTHER LOW LYING AREAS ARE SUBJECT TO FLASH FLOODING.

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.

LAT...LON 4078 10504 4044 10498 4040 10521 4052 10561
          4078 10549

RJK

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 5, 7:55 PM MDT, 1 hour 17 minutes before
COZ035-036-038>041-043-060230-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER COLORADO
755 PM MDT TUE AUG 5 1997

...SHOWERS AND THUNDERSTORMS PRODUCING ONE HALF TO ONE INCH OF
RAINFALL OVER THE URBAN CORRIDOR...

AT 755 PM WEATHER SERVICE RADAR INDICATED A LINE OF SHOWERS AND
THUNDERSTORMS PUSHING ACROSS THE URBAN CORRIDOR...FROM FORT COLLINS
TO THE SOUTHERN DENVER METRO AREA.  RAINFALL MEASUREMENTS AND RADAR
ESTIMATES INDICATE THESE SHOWERS WERE PRODUCING 0.50 TO 1.00 INCH OF
RAIN AS THEY PUSHED SOUTHEASTWARD AT 25 MPH.

PEOPLE ALONG THE FRONT RANGE URBAN CORRIDOR SHOULD BE ON THE LOOKOUT
FOR MINOR URBAN FLOODING OF LOW LYING AREAS...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.

RJK
Special weather statement, Aug 5, 8:00 PM MDT, 1 hour 12 minutes before
COZ035-036-038>041-043-060230-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER COLORADO
755 PM MDT TUE AUG 5 1997

...SHOWERS AND THUNDERSTORMS PRODUCING ONE HALF TO ONE INCH OF
RAINFALL OVER THE URBAN CORRIDOR...

AT 755 PM WEATHER SERVICE RADAR INDICATED A LINE OF SHOWERS AND
THUNDERSTORMS PUSHING ACROSS THE URBAN CORRIDOR...FROM FORT COLLINS
TO THE SOUTHERN DENVER METRO AREA.  RAINFALL MEASUREMENTS AND RADAR
ESTIMATES INDICATE THESE SHOWERS WERE PRODUCING 0.50 TO 1.00 INCH OF
RAIN AS THEY PUSHED SOUTHEASTWARD AT 25 MPH.

PEOPLE ALONG THE FRONT RANGE URBAN CORRIDOR SHOULD BE ON THE LOOKOUT
FOR MINOR URBAN FLOODING OF LOW LYING AREAS...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.

RJK
Special weather statement, Aug 5, 8:40 PM MDT, 32 minutes before
COZ035>050-061200-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
840 PM MDT TUE AUG 5 1997

...FLASH FLOOD WATCH FOR NORTHEASTERN COLORADO TO CONTINUE...

THE FLASH FLOOD WATCH FOR MOST OF NORTHEASTERN COLORADO WILL
CONTINUE THROUGH THE NIGHT. RAINFALL AMOUNTS OF 1 TO 2 INCHES HAVE
BEEN REPORTED BY RADAR ACROSS THE URBAN CORRIDOR THIS EVENING
...WITH LIGHTER AMOUNTS OVER MUCH OF THE REMAINDER OF NORTHEASTERN
COLORADO.

A SERIES OF DISTURBANCES WILL BE AFFECTING NORTHEASTERN COLORADO
DURING THE REMAINDER OF THE NIGHT. TIMING AND EXACT LOCATION
OF THESE DISTURBANCES WILL BE DIFFICULT...BUT ALL AREAS OF
NORTHEASTERN COLORADO BELOW ABOUT 8000 FEET WILL BE SUSCEPTIBLE TO
HEAVY RAINS AND FLASH FLOODING.

REMEMBER THAT HEAVY RAINS DURING THE PAST SEVERAL DAYS HAVE
SIGNIFICANTLY DECREASED THE RAINFALL NEEDED TO PRODUCE SIGNIFICANT
FLOODING. PERSONS ALONG SMALL STREAMS AND IN URBAN AREAS SHOULD BE
PARTICULARLY ALERT FOR FLASH FLOODING. THERE WILL BE LITTLE TIME TO
REACT AFTER THE HEAVY RAINS BEGIN AND NECESSARY PRECAUTIONS SHOULD
BE TAKEN BEFOREHAND.

TUNNELL/TA
Special weather statement, Aug 5, 8:42 PM MDT, 30 minutes before
COZ035>050-061200-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
840 PM MDT TUE AUG 5 1997

...FLASH FLOOD WATCH FOR NORTHEASTERN COLORADO TO CONTINUE...

THE FLASH FLOOD WATCH FOR MOST OF NORTHEASTERN COLORADO WILL
CONTINUE THROUGH THE NIGHT. RAINFALL AMOUNTS OF 1 TO 2 INCHES HAVE
BEEN REPORTED BY RADAR ACROSS THE URBAN CORRIDOR THIS EVENING
...WITH LIGHTER AMOUNTS OVER MUCH OF THE REMAINDER OF NORTHEASTERN
COLORADO.

A SERIES OF DISTURBANCES WILL BE AFFECTING NORTHEASTERN COLORADO
DURING THE REMAINDER OF THE NIGHT. TIMING AND EXACT LOCATION
OF THESE DISTURBANCES WILL BE DIFFICULT...BUT ALL AREAS OF
NORTHEASTERN COLORADO BELOW ABOUT 8000 FEET WILL BE SUSCEPTIBLE TO
HEAVY RAINS AND FLASH FLOODING.

REMEMBER THAT HEAVY RAINS DURING THE PAST SEVERAL DAYS HAVE
SIGNIFICANTLY DECREASED THE RAINFALL NEEDED TO PRODUCE SIGNIFICANT
FLOODING. PERSONS ALONG SMALL STREAMS AND IN URBAN AREAS SHOULD BE
PARTICULARLY A\LERT FOR FLASH FLOODING. THERE WILL BE LITTLE TIME TO
REACT AFTER THE HEAVY RAINS BEGIN AND NECESSARY PRECAUTIONS SHOULD
BE TAKEN BEFOREHAND.

TUNNELL/TA

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 6, 2:16 PM MDTTornado WarningBOUMorgan, Weld29 min

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.