Alert archive / Colorado / Flash Flood Warnings in 2012

Flash Flood Warning 9, NWS Denver/Boulder, CO

July 5, 2012Boulder County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 5, 2012, 4:17 PM MDT for Boulder County, Colorado. It was in force for 118 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jul 5, 2012, 4:17 PM MDT (22:17 UTC)
Expired
Jul 5, 2012, 6:15 PM MDT
In force
118 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Flood severity
None

County Boulder County, CO

The radar

The Denver radar (KFTG), 79 km from the middle of the area, began a volume at 22:19 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.

What was reported inside it

TimeReportWhereRemark
Jul 5, 4:40 PM MDTFLASH FLOOD2 Sse Gold Hill, COA THUNDERSTORM PRODUCED HEAVY RAIN ACROSS THE FOURMILE BURN SCAR. NINE TENTHS OF AN INCH OF RAIN WAS REPORTED IN 30 MINUTES AT SUNSHINE. LOTS OF DEBRIS WAS REPORTED ACROSS FOURMILE DRIVE AT NANCY MINE ROAD. THERE WAS A ROCKSLIDE AT FOURMILE AND LOGAN MILL ROAD

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 10.3 hours before the alert went out and 186 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 2012-07-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 313 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 2012-07-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -29 square meters per square second.1939Sfc1 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
313 J/kg
Mixed-layer CIN
-227 J/kg
Mixed-layer LCL
1462 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
-29 m²/s²
0-3 km storm-relative helicity
97 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.

319 
WGUS55 KBOU 052217
FFWBOU
COC013-060015-
/O.NEW.KBOU.FF.W.0009.120705T2217Z-120706T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
417 PM MDT THU JUL 5 2012

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

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

* UNTIL 615 PM MDT

* AT 416 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM NEAR SUMMERVILLE...OR 33 MILES
  NORTHWEST OF DENVER. THIS STORM WAS MOVING NORTH AT 20 MPH.

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

TRAINED WEATHER SPOTTERS REPORT THAT QUARTER OF AN INCH OF RAIN FELL 
IN 10 MINUTES.  ADDITIONAL RAIN IS EXPECTED FOR THE NEXT HOUR.

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.

THIS IS A LIFE THREATENING SITUATION. HEAVY RAINFALL WILL CAUSE
EXTENSIVE AND SEVERE FLASH FLOODING OF CREEKS...STREAMS...AND DITCHES
IN THE FOURMILE BURN AREA. SOME DRAINAGE BASINS IMPACTED INCLUDE
FOURMILE CREEK...GOLD RUN...AND FOURMILE CANYON CREEK. SEVERE DEBRIS
FLOWS CAN ALSO BE ANTICIPATED ACROSS ROADS. ROADS AND DRIVEWAYS MAY
BE WASHED AWAY IN PLACES. IF YOU ENCOUNTER FLOOD WATERS...CLIMB TO
SAFETY.

&&

LAT...LON 4007 10544 4009 10533 4003 10535 4002 10543

$$
3 follow-up statements
452 
WGUS75 KBOU 052307
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
507 PM MDT THU JUL 5 2012

COC013-060015-
/O.CON.KBOU.FF.W.0009.000000T0000Z-120706T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BOULDER CO-
507 PM MDT THU JUL 5 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 PM MDT FOR
CENTRAL BOULDER COUNTY...

AT 505 PM MDT...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED FLASH 
FLOODING IN THE FOURMILE BURN AREA. THE STRONGEST THUNDERSTORM HAD 
MOVED NORTH OF THE BURN AREA...BUT ANOTHER THUNDERSTORM WAS LOCATED 
NEAR SUNSHINE...OR ABOUT 31 MILES NORTHWEST OF DENVER. THIS STORM 
WAS MOVING NORTH AT 25 MPH.

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

FLASH FLOODING WAS REPORTED IN GOLD RUN...AT THE INTERSECTION OF 
GOLD RUN ROAD AND FOURMILE CANYON DRIVE...AND IN THE CRISMAN AREA.

AUTOMATED RAIN GAUGES INDICATE THAT BETWEEN 0.5 AND 0.9 INCHES OF 
RAIN FELL OVER THE BURN AREA IN 30 MINUTES.

FLOODING MAY ALSO OCCUR DOWNSTREAM OF THE BURN AREA ALONG FOURMILE 
CANYON CREEK TO THE MOUTH OF THE CANYON AND ALONG FOURMILE CREEK TO 
HIGHWAY 119.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A LIFE THREATENING SITUATION. HEAVY RAINFALL WILL CAUSE
EXTENSIVE AND SEVERE FLASH FLOODING OF CREEKS...STREAMS...AND DITCHES
IN THE FOURMILE BURN AREA. SOME DRAINAGE BASINS IMPACTED INCLUDE
FOURMILE CREEK...GOLD RUN...AND FOURMILE CANYON CREEK. SEVERE DEBRIS
FLOWS CAN ALSO BE ANTICIPATED ACROSS ROADS. ROADS AND DRIVEWAYS MAY
BE WASHED AWAY IN PLACES. IF YOU ENCOUNTER FLOOD WATERS...CLIMB TO
SAFETY.

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.

DO NOT UNDERESTIMATE THE POWER OF FLOOD WATERS. ONLY A FEW INCHES OF
RAPIDLY FLOWING WATER CAN QUICKLY CARRY AWAY YOUR VEHICLE.

&&

LAT...LON 4007 10544 4009 10533 4003 10535 4002 10543

$$
GIMMESTAD
616 
WGUS75 KBOU 052345
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
545 PM MDT THU JUL 5 2012

COC013-060015-
/O.CON.KBOU.FF.W.0009.000000T0000Z-120706T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BOULDER CO-
545 PM MDT THU JUL 5 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 PM MDT FOR THE 
FOURMILE BURN AREA IN CENTRAL BOULDER COUNTY...

AT 543 PM MDT...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED THAT FLASH 
FLOODING WAS SUBSIDING IN THE FOURMILE BURN AREA. ROCK AND MUD 
SLIDES OCCURRED ALONG FOURMILE CANYON DRIVE NEAR LOGAN MILL ROAD... 
NANCY MINE ROAD...AND WALLSTREET RESULTING IN THE ROAD BEING CLOSED. 
THERE WAS ALSO FLOODING ALONG GOLD RUN...AND GOLD RUN ROAD WAS 
CLOSED.

RUNOFF WILL BE SUBSIDING OVER THE NEXT 30 MINUTES BUT RESIDENTS 
SHOULD BE ALERT TO POSSIBLE ROAD DAMAGE AND STAY OUT OF FLOODED 
AREAS. IT ONLY TAKES A FEW INCHES OF RAPIDLY FLOWING WATER TO KNOCK 
YOU OFF OF YOUR FEET.

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

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. STAY OUT OF FLOODED AREAS.

&&

LAT...LON 4007 10544 4009 10533 4003 10535 4002 10543

$$
GIMMESTAD
307 
WGUS75 KBOU 060018
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
618 PM MDT THU JUL 5 2012

COC013-060027-
/O.EXP.KBOU.FF.W.0009.000000T0000Z-120706T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BOULDER CO-
618 PM MDT THU JUL 5 2012

...THE FLASH FLOOD WARNING HAS EXPIRED FOR THE FOURMILE BURN AREA IN 
CENTRAL BOULDER COUNTY...

FLOOD WATERS HAVE SUBSIDED AND FLASH FLOODING IS NO LONGER EXPECTED. 
ROAD CLOSURES ON FOURMILE CANYON DRIVE AND GOLD RUN ROAD MAY REMAIN 
IN EFFECT THIS EVENING AS ROCK AND MUD SLIDES AND EROSION TO ROADS 
IN THE AREA ARE CLEANED UP.

LAT...LON 4007 10544 4009 10533 4003 10535 4002 10543

$$
GIMMESTAD

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 4, 8:25 PM MDTSpecial Weather StatementBOUPhillips35 min
Jul 5, 1:07 PM MDTSevere Thunderstorm WarningBOUBoulder, Grand, Larimer27 min
Jul 5, 2:11 PM MDTAreal Flood AdvisoryBOULarimer116 min
Jul 5, 2:54 PM MDTAreal Flood AdvisoryBOUClear Creek96 min
Jul 5, 3:56 PM MDTAreal Flood AdvisoryBOUBoulder94 min
Jul 5, 4:42 PM MDTAreal Flood AdvisoryBOUBoulder68 min
Jul 5, 4:42 PM MDTAreal Flood AdvisoryBOUBoulder93 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.