Alert archive / Colorado / Flash Flood Warnings in 2012

Flash Flood Warning 23, NWS Denver/Boulder, CO

July 30, 2012Boulder County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 30, 2012, 3:27 PM MDT for Boulder County, Colorado. It was in force for 78 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 30, 2012, 3:27 PM MDT (21:27 UTC)
Expired
Jul 30, 2012, 4:45 PM MDT
In force
78 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Flood severity
None

County Boulder County, CO

The radar

The Denver radar (KFTG), 77 km from the middle of the area, began a volume at 21:27 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, 9.5 hours before the alert went out and 184 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 2012-07-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 36 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 2012-07-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 4 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
36 J/kg
Mixed-layer CIN
-260 J/kg
Mixed-layer LCL
2058 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
4 m²/s²
0-3 km storm-relative helicity
48 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.

170 
WGUS55 KBOU 302127
FFWBOU
COC013-302330-
/O.NEW.KBOU.FF.W.0023.120730T2127Z-120730T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
327 PM MDT MON JUL 30 2012

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL BOULDER COUNTY IN NORTHEAST COLORADO

* UNTIL 530 PM MDT

* AT 324 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM 3 MILES SOUTHWEST OF GOLD
  HILL...OR 34 MILES NORTHWEST OF DENVER. THIS STORM WAS MOVING EAST
  AT 15 MPH.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  WALLSTREET...SUNSHINE...SUMMERVILLE...SALINA...CRISMAN AND GOLD
  HILL.

RAIN GAUGES IN THE FOUR MILE BURN AREA HAVE ALREADY RECORDED UP TO 
0.70 INCH OF RAIN SINCE 3:00 PM MDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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. TURN AROUND...DO NOT DROWN.

HEAVY RAINFALL WILL CAUSE FLASH FLOODING OF CREEKS...STREAMS...AND
DITCHES IN THE FOURMILE BURN AREA. SOME DRAINAGE BASINS AFFECTED BY
EXCESSIVE RUNOFF INCLUDE FOURMILE CREEK...GOLD RUN...AND FOURMILE
CANYON CREEK. WATER WILL BE FLOWING DOWN ROADWAYS. ROCK SLIDES OR
DEBRIS FLOWS CAN ALSO BE EXPECTED.

&&

LAT...LON 4009 10536 4005 10533 4001 10539 4006 10544

$$



RJK
2 follow-up statements
149 
WGUS75 KBOU 302155
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
355 PM MDT MON JUL 30 2012

COC013-302330-
/O.CON.KBOU.FF.W.0023.000000T0000Z-120730T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BOULDER CO-
355 PM MDT MON JUL 30 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 PM MDT FOR THE 
FOUR MILE BURN AREA IN CENTRAL BOULDER COUNTY...

AT 347 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED THE 
HEAVY RAIN HAS PUSHED EASTWARD AND IS NO LONGER FALLING OVER THE 
FOUR MILE BURN AREA IN CENTRAL BOULDER COUNTY.  

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
WALLSTREET...SUNSHINE...SUMMERVILLE...SALINA...CRISMAN AND GOLD HILL.

AUTOMATED RAIN GAUGES INDICATE THAT 0.90 TO 1.15 INCHES OF RAIN HAVE 
FALLEN OVER THE NORTHERN AND NORTHEASTERN PORTIONS OF THE FOUR MILE 
BURN AREA.  THE SOUTHERN HALF RECEIVED LESSER AMOUNTS...MOSTLY UNDER 
0.40 INCHES.  THIS RAIN FELL FROM ABOUT 3:10 PM MDT TO 3:40 PM MDT.

WASHES AND ROCKS WERE REPORTED GOING ACROSS LEE HILL ROAD AT 3:39 PM 
MDT. ALSO...GOLD RUN ROAD IS CLOSED AT DIXON.  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

HEAVY RAINFALL WILL CAUSE FLASH FLOODING OF CREEKS...STREAMS...AND
DITCHES IN THE FOURMILE BURN AREA. SOME DRAINAGE BASINS AFFECTED BY
EXCESSIVE RUNOFF INCLUDE FOURMILE CREEK...GOLD RUN...AND FOURMILE
CANYON CREEK. WATER WILL BE FLOWING DOWN ROADWAYS. ROCK SLIDES OR
DEBRIS FLOWS CAN ALSO BE EXPECTED.

MOST FLASH FLOOD DEATHS OCCUR IN AUTOMOBILES. DO NOT ATTEMPT TO CROSS
BRIDGES...DIPS...OR OTHER LOW SPOTS IF WATER COVERS THE ROADWAY.
NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL ONE...ON FOOT. TO
ESCAPE RISING WATER CLIMB TO HIGHER GROUND.

&&

LAT...LON 4009 10536 4005 10533 4001 10539 4006 10544

$$



RJK
465 
WGUS75 KBOU 302245
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
445 PM MDT MON JUL 30 2012

COC013-302249-
/O.CAN.KBOU.FF.W.0023.000000T0000Z-120730T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BOULDER CO-
445 PM MDT MON JUL 30 2012

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR THE FOUR MILE BURN 
AREA IN CENTRAL BOULDER COUNTY...

THE RAIN AS WELL AS THE FLOODING OVER THE NORTHERN HALF OF THE FOUR 
MILE BURN AREA IN CENTRAL BOULDER COUNTY HAS ENDED.  FLOOD WATERS 
HAVE SUBSIDED AND FLASH FLOODING IS NO LONGER EXPECTED.

AUTOMATED RAIN GAUGES INDICATE THAT 0.90 TO 1.15 INCHES OF RAIN FELL
OVER THE NORTHERN AND NORTHEASTERN PORTIONS OF THE FOUR MILE BURN 
AREA.  THE SOUTHERN HALF RECEIVED LESSER AMOUNTS...MOSTLY UNDER 0.40 
INCHES.  THIS RAIN FELL FROM ABOUT 3:10 PM MDT TO 3:40 PM MDT.

THERE WERE REPORTS OF ROCKS AND MUD OVER GOLD RUN ROAD...AND OVER 
ROADS IN DIXON AND 4 MILE CANYON.

LAT...LON 4009 10536 4005 10533 4001 10539 4006 10544

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 30, 2:09 PM MDTSpecial Weather StatementBOUJefferson36 min
Jul 30, 2:30 PM MDTSpecial Weather StatementBOUGrand30 min
Jul 30, 3:04 PM MDTSpecial Weather StatementBOUDouglas26 min
Jul 30, 3:12 PM MDTSevere Thunderstorm WarningBOUDouglas22 min

Nearby

Flash Flood Warnings in Colorado, 2012Every flash flood warning in 2012

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.