Alert archive / Colorado / Flash Flood Warnings in 2011

Flash Flood Warning 2, NWS Denver/Boulder, CO

May 24, 2011Washington County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at May 24, 2011, 2:55 PM MDT for Washington County, Colorado. It was in force for 6 hr. 2 reports 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
May 24, 2011, 2:55 PM MDT (20:55 UTC)
Expired
May 24, 2011, 9:00 PM MDT
In force
6 hr
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Flood severity
None

County Washington County, CO

The radar

The Goodland radar (KGLD), 140 km from the middle of the area, began a volume at 20:56 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
May 24, 4:15 PM MDTHEAVY RAIN 3.2710 Nw Yuma, CO2.54 INCHES SINCE 7 A.M
May 24, 5:50 PM MDTFLASH FLOOD6 S Lone Star, COWATER ONE FOOT DEEP RUNNING OVER ROAD ZZ AT SEVERAL LOCATIONS

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, 8.9 hours before the alert went out and 52 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 2011-05-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 291 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 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 2011-05-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 32 square meters per square second.19395878Sfc1 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
291 J/kg
Mixed-layer CIN
-122 J/kg
Mixed-layer LCL
996 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
32 m²/s²
0-3 km storm-relative helicity
85 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

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

441 
WGUS55 KBOU 242055
FFWBOU
COC121-250000-
/O.NEW.KBOU.FF.W.0002.110524T2055Z-110525T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
255 PM MDT TUE MAY 24 2011

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHEASTERN WASHINGTON COUNTY IN NORTHEAST COLORADO

* UNTIL 600 PM MDT

* AT 253 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM 6 MILES NORTHEAST OF OTIS...OR
  18 MILES EAST OF AKRON. THIS STORM WAS MOVING WEST AT 15 MPH.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO PLATNER...
  OTIS...LONE STAR AND BURDETT.

TRAINED WEATHER SPOTTERS REPORT THAT ONE AND A HALF INCHES OF RAIN  
HAVE FALLEN FROM THIS STORM IN THE LAST HOUR. THIS STORM IS 
PRODUCING RAIN OVER ALREADY RAIN SOAKED SOILS. 

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.

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

&&

LAT...LON 4035 10279 4000 10279 3996 10280 4013 10309
      4043 10315 4043 10277 4035 10278

$$
3 follow-up statements
130 
WGUS75 KBOU 242256
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
456 PM MDT TUE MAY 24 2011

COC121-250000-
/O.CON.KBOU.FF.W.0002.000000T0000Z-110525T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON CO-
456 PM MDT TUE MAY 24 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 600 PM MDT FOR
NORTHEASTERN WASHINGTON COUNTY...

AT 453 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
CONTINUOUS HEAVE RAIN OVER NORTHEASTERN WASHINGTON COUNTY.

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO 
PLATNER...OTIS...LONE STAR AND BURDETT. CREEKS THAT WILL BE AFFECTED 
WILL BE SURVEYOR AND ROCK CREEKS.

TRAINED WEATHER SPOTTERS REPORT THAT 2.54 INCHES OF RAIN HAVE FALLEN 
FROM THIS STORM SINCE 7 AM. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 4035 10279 4000 10279 3996 10280 4013 10309
      4043 10315 4043 10277 4035 10278

$$
292 
WGUS55 KBOU 242358
FFWBOU
COC121-250300-
/O.EXT.KBOU.FF.W.0002.000000T0000Z-110525T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
558 PM MDT TUE MAY 24 2011

THE NATIONAL WEATHER SERVICE IN DENVER HAS EXTENDED THE

* FLASH FLOOD WARNING FOR...
  NORTHEASTERN WASHINGTON COUNTY IN NORTHEAST COLORADO

* UNTIL 900 PM MDT

* AT 556 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  CONTINUOUS HEAVY RAIN OVER NORTHEASTERN WASHINGTON COUNTY.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO PLATNER...
  OTIS...LONE STAR AND BURDETT.

TRAINED WEATHER SPOTTERS REPORT THAT OVER 2.54 INCHES OF RAIN HAVE
FALLEN FROM THIS STORM SINCE 7 AM THIS MORNING. OTHER TRAINED 
SPOTTERS HAVE REPORTED MANY SECTIONS OF ROADS ARE INUNDATED WITH
A FOOT OR MORE OF WATER. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

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 4035 10279 4000 10279 3996 10280 4013 10309
      4043 10315 4043 10277 4035 10278

$$
624 
WGUS75 KBOU 250222
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
822 PM MDT TUE MAY 24 2011

COC121-250300-
/O.CON.KBOU.FF.W.0002.000000T0000Z-110525T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WASHINGTON CO-
822 PM MDT TUE MAY 24 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 900 PM MDT FOR
NORTHEASTERN WASHINGTON COUNTY...

AT 820 PM MDT...NATIONAL WEATHER SERVICE DOPPLER INDICATED THAT THE 
HEAVIEST RAIN HAD ENDED IN THE WARNED AREA.  HOWEVER...HEAVIER RAIN 
EARLIER THIS EVENING COMBINED WITH ADDITIONAL LIGHT RAINFALL MAY 
CONTINUE TO PRODUCE FLASH FLOODING...ESPECIALLY ALONG CREEKS AND 
STREAMS.  COUNTY ROAD ZZ SOUTH OF LONE STAR WAS FLOODED BY A FOOT OR 
MORE OF WATER EARLIER THIS EVENING.

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
PLATNER...OTIS...LONE STAR AND BURDETT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY AS THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO
CROSS SAFELY. DO NOT UNDERESTIMATE THE POWER OF FLOOD WATERS. ONLY A
FEW INCHES OF RAPIDLY FLOWING WATER CAN QUICKLY CARRY AWAY YOUR
VEHICLE. TURN AROUND...DO NOT DROWN.

&&

LAT...LON 4035 10279 4000 10279 3996 10280 4013 10309
      4043 10315 4043 10277 4035 10278

$$
BARJENBRUCH

The office that day

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

IssuedProductOfficeCountiesLasted
May 23, 6:39 PM MDTSpecial Weather StatementBOUSedgwick36 min
May 24, 1:35 AM MDTSpecial Weather StatementBOUElbert40 min
May 24, 9:19 AM MDTSevere Thunderstorm WarningBOULincoln41 min
May 24, 9:27 AM MDTFlash Flood WatchBOULogan, Morgan, Phillips, Sedgwick, Washington19 hr
May 24, 12:01 PM MDTSpecial Weather StatementBOULincoln44 min
May 24, 12:29 PM MDTAreal Flood AdvisoryBOUMorgan116 min
May 24, 3:45 PM MDTSpecial Weather StatementBOUPhillips45 min
May 24, 3:56 PM MDTFlash Flood WarningBOUPhillips6 hr

Nearby

Flash Flood Warnings in Colorado, 2011Every flash flood warning in 2011

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.