Alert archive / Colorado / Flash Flood Warnings in 2011

Flash Flood Warning 18, NWS Denver/Boulder, CO

July 13, 2011Weld County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 13, 2011, 12:16 AM MDT for Weld 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 as issued.

The facts

Issued
Jul 13, 2011, 12:16 AM MDT (06:16 UTC)
Expired
Jul 13, 2011, 3:15 AM MDT
In force
3 hr
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Flood severity
None

County Weld County, CO

The radar

The Cheyenne radar (KCYS), 53 km from the middle of the area, began a volume at 06:17 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, 6.3 hours before the alert went out and 143 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 2011-07-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 596 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 00:00Z on 2011-07-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -12 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
596 J/kg
Mixed-layer CIN
-61 J/kg
Mixed-layer LCL
1449 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
-12 m²/s²
0-3 km storm-relative helicity
256 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.2

Open this sounding in Storm Lab

The text

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

145 
WGUS55 KBOU 130616
FFWBOU
COC123-130915-
/O.NEW.KBOU.FF.W.0018.110713T0616Z-110713T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
1216 AM MDT WED JUL 13 2011

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHERN WELD COUNTY IN NORTHEAST COLORADO

* UNTIL 315 AM MDT

* AT 1211 AM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM 7 MILES EAST OF PAWNEE
  BUTTES...OR 36 MILES WEST OF STERLING. THIS STORM WAS MOVING
  NORTHEAST AT 30 MPH.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO NATURAL
  FORT...ROCKPORT...PURCELL...PIERCE...PAWNEE BUTTES...NUNN...
  KEOTA...HEREFORD...GROVER...CARR...BRIGGSDALE AND AULT.

DOPPLER RADAR ESTIMATES THAT BETWEEN 2 AND 5 INCHES OF RAIN HAS 
FALLEN ACROSS MOST OF NORTHERN WELD COUNTY...WITH THE HEAVIEST 
RAINFALL EAST OF HIGHWAY 85 AND NORTH OF HIGHWAY 14.

A CITIZEN REPORTED WATER WASHING OVER A ROAD NEAR COUNTY ROAD 100 
AND COUNTY ROAD 27 NORTHWEST OF NUNN.  EARLIER...FLOODING WAS ALSO 
REPORTED AT COUNTY ROAD 100 AND COUNTY ROAD 77.

THIS FLASH FLOOD WARNING ALSO INCLUDES THE FOLLOWING STREAMS...
COAL BANK CREEK...WILD HORSE CREEK...WILLOW CREEK...CROW 
CREEK...NORTH PAWNEE CREEK...SPRING CREEK...AND TWO MILE CREEK.

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.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODS AND FLASH FLOODS. IF FLASH FLOODING IS OBSERVED ACT
QUICKLY. MOVE UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY
IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

&&

LAT...LON 4100 10358 4067 10358 4052 10454 4056 10495
      4066 10495 4067 10494 4075 10494 4099 10493

$$
BARJENBRUCH
2 follow-up statements
708 
WGUS75 KBOU 130715
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
115 AM MDT WED JUL 13 2011

COC123-130915-
/O.CON.KBOU.FF.W.0018.000000T0000Z-110713T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WELD CO-
115 AM MDT WED JUL 13 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 315 AM MDT FOR
NORTHERN WELD COUNTY...

AT 113 AM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED THE 
HEAVIEST RAIN WAS MOVING OUT OF NORTHERN WELD COUNTY.  

DOPPLER RADAR ESTIMATES THAT BETWEEN 2 AND 5 INCHES OF RAIN FELL 
ACROSS MOST OF NORTHERN WELD COUNTY EARLIER TONIGHT...WITH THE 
HEAVIEST RAINFALL EAST OF HIGHWAY 85 AND NORTH OF HIGHWAY 14.  

A CITIZEN REPORTED WATER WASHING OVER A ROAD NEAR COUNTY ROAD 100 
AND COUNTY ROAD 27 NORTHWEST OF NUNN.  EARLIER...FLOODING WAS ALSO 
REPORTED AT COUNTY ROAD 100 AND COUNTY ROAD 77.

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO 
NATURAL FORT...ROCKPORT...PURCELL...PIERCE...PAWNEE 
BUTTES...NUNN...KEOTA...HEREFORD...GROVER...CARR...BRIGGSDALE AND 
AULT.

THIS FLASH FLOOD WARNING ALSO INCLUDES THE FOLLOWING STREAMS...COAL 
BANK CREEK...WILD HORSE CREEK...WILLOW CREEK...CROW CREEK...NORTH 
PAWNEE CREEK...SPRING CREEK...AND TWO MILE CREEK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODS AND FLASH FLOODS. IF FLASH FLOODING IS OBSERVED ACT
QUICKLY. MOVE UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY
IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

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 4100 10358 4067 10358 4052 10454 4056 10495
      4066 10495 4067 10494 4075 10494 4099 10493

$$
BARJENBRUCH
296 
WGUS75 KBOU 130915
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
315 AM MDT WED JUL 13 2011

COC123-130919-
/O.EXP.KBOU.FF.W.0018.000000T0000Z-110713T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WELD CO-
315 AM MDT WED JUL 13 2011

...THE FLASH FLOOD WARNING WILL EXPIRE AT 315 AM MDT FOR NORTHERN
WELD COUNTY...

THE STORMS THAT PROMPTED THE WARNING HAVE EXITED THE AREA. 
THUNDERSTORMS THAT FORMED TUESDAY AFTERNOON AND EVENING PRODUCED 
BETWEEN 2 AND 5 INCHES OF RAINFALL ACROSS NORTHERN WELD COUNTY.  
THERE HAVE BEEN SEVERAL REPORTS OF FLOODED OR DAMAGED ROADS AROUND 
RURAL NORTHERN WELD COUNTY. AREAS THAT WERE HARDEST HIT BY THE HEAVY 
RAIN STRETCHED FROM NUNN NORTHEAST TO GROVER AND TO THE NORTH OF NEW 
RAYMER.   

MOTORISTS SHOULD CONTINUE TO USE CAUTION IF THEY ENCOUNTER ROADWAYS 
UNDER WATER. ROAD BEDS MAY BE WASHED OUT AND IT WILL BE DIFFICULT TO 
ESTIMATE THE DEPTH OF STANDING OR FLOWING WATER.  

LAT...LON 4100 10358 4067 10358 4052 10454 4056 10495
      4066 10495 4067 10494 4075 10494 4099 10493

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 12, 6:34 PM MDTFlash Flood WarningBOUArapahoe, Elbert2 hr
Jul 12, 6:39 PM MDTSevere Thunderstorm WarningBOUArapahoe, Elbert51 min
Jul 12, 7:03 PM MDTTornado WarningBOUElbert42 min
Jul 12, 7:19 PM MDTFlash Flood WarningBOUArapahoe, Elbert91 min
Jul 12, 7:23 PM MDTSevere Thunderstorm WarningBOUWeld52 min
Jul 12, 7:27 PM MDTTornado WarningBOUElbert48 min
Jul 12, 7:34 PM MDTTornado WarningBOUWeld41 min
Jul 12, 7:45 PM MDTTornado WarningBOUElbert45 min
Jul 12, 7:48 PM MDTAreal Flood AdvisoryBOUWeld87 min
Jul 12, 8:05 PM MDTSevere Thunderstorm WarningBOUWeld40 min
Jul 12, 8:17 PM MDTTornado WarningBOUElbert43 min
Jul 12, 8:21 PM MDTSevere Thunderstorm WarningBOUWeld54 min
Jul 12, 8:33 PM MDTFlash Flood WarningBOUArapahoe, Elbert3 hr
Jul 12, 8:44 PM MDTFlash Flood WarningBOUWeld2 hr
Jul 12, 9:00 PM MDTSevere Thunderstorm WarningBOUElbert60 min
Jul 12, 9:04 PM MDTSevere Thunderstorm WarningBOUWeld56 min
Jul 12, 9:10 PM MDTTornado WarningBOUWeld34 min
Jul 12, 9:15 PM MDTAreal Flood AdvisoryBOUAdams, Arapahoe, Denver, Jefferson90 min
Jul 12, 9:30 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Denver44 min
Jul 12, 9:40 PM MDTAreal Flood AdvisoryBOUBoulder95 min
Jul 12, 9:59 PM MDTSevere Thunderstorm WarningBOUWeld61 min
Jul 12, 10:35 PM MDTAreal Flood AdvisoryBOULarimer, Weld115 min
Jul 12, 10:48 PM MDTFlash Flood WarningBOUWeld3 hr
Jul 12, 10:54 PM MDTFlash Flood WarningBOULarimer2 hr
Jul 12, 11:19 PM MDTAreal Flood WarningBOUArapahoe, Elbert6 hr
Jul 13, 12:04 AM MDTRiver Flood AdvisoryBOUAdams10 hr
Jul 13, 12:32 AM MDTRiver Flood AdvisoryBOUWeld47 hr
Jul 13, 12:37 AM MDTAreal Flood AdvisoryBOUWeld83 min
Jul 13, 1:11 AM MDTAreal Flood AdvisoryBOULogan94 min
Jul 13, 2:01 PM MDTSpecial Weather StatementBOUElbert29 min
Jul 13, 2:22 PM MDTSevere Thunderstorm WarningBOUElbert38 min
Jul 13, 2:42 PM MDTAreal Flood AdvisoryBOUElbert93 min
Jul 13, 2:58 PM MDTSevere Thunderstorm WarningBOUElbert38 min
Jul 13, 3:52 PM MDTSevere Thunderstorm WarningBOUElbert38 min
Jul 13, 4:22 PM MDTSevere Thunderstorm WarningBOUElbert16 min
Jul 13, 5:08 PM MDTSpecial Weather StatementBOUJefferson52 min
Jul 13, 5:53 PM MDTAreal Flood AdvisoryBOUBoulder82 min
Jul 13, 5:56 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe, Denver, Douglas, Jefferson49 min

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.