Alert archive / Colorado / Flash Flood Warnings in 2012

Flash Flood Warning 12, NWS Denver/Boulder, CO

July 6, 2012Larimer County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 6, 2012, 5:38 PM MDT for Larimer County, Colorado. It was in force for 103 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 6, 2012, 5:38 PM MDT (23:38 UTC)
Expired
Jul 6, 2012, 7:21 PM MDT
In force
103 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Flood severity
None

County Larimer County, CO

The radar

The Cheyenne radar (KCYS), 74 km from the middle of the area, began a volume at 23:42 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, 11.6 hours before the alert went out and 204 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 2012-07-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2012-07-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2053 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
-1 m²/s²
0-3 km storm-relative helicity
28 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.

092 
WGUS55 KBOU 062338
FFWBOU
COC069-070230-
/O.NEW.KBOU.FF.W.0012.120706T2338Z-120707T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
538 PM MDT FRI JUL 6 2012

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL LARIMER COUNTY IN NORTH CENTRAL COLORADO

* UNTIL 830 PM MDT

* AT 525 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM 14 MILES SOUTH OF BUCKHORN
  MOUNTAIN...OR 14 MILES SOUTHWEST OF FORT COLLINS. THIS STORM WAS
  MOVING NORTH AT 10 MPH.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO THE HIGH   
  PARK BURN AREA...POUDRE PARK...MISHOWAKA AND BUCKHORN MOUNTAIN.

THIS INCLUDES THE FOLLOWING STREAMS AND DRAINAGES...
CACHE LA POUDRE RIVER...SOUTH FORK CACHE LA POUDRE RIVER...LITTLE
BEAVER CREEK...PENDERGRASS CREEK...PENNOCK CREEK...BENNETT CREEK...
ELD CREEK...NORTH FORK CACHE LA POUDRE RIVER...MILL CREEK...GORDON
CREEK...MANHATTAN CREEK...REDSTONE CREEK...BUCKHORN CREEK AND SHEEP
CREEK.

ANOTHER AREA OF THUNDERSTORMS OVER SOUTHERN LARIMER COUNTY IS 
EXPECTED TO MOVE INTO THE HIGH PARK BURN AREA WITHIN THE HOUR.  
SEVERAL MUDSLIDES AND SOME FLOODING HAS ALREADY OCCURRED IN THE BURN 
AREA FROM STORMS EARLIER THIS AFTERNOON...AND ADDITIONAL RAINFALL 
WILL CONTINUE TO EXACERBATE THE POTENTIAL FOR FLASH FLOODING. 

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 CREEKS
AND STREAMS...ROADS...AND ROADSIDE CULVERTS. THE HEAVY RAINS COULD 
ALSO TRIGGER ROCK SLIDES OR DEBRIS FLOWS IN THE HIGH PARK BURN AREA.

&&

LAT...LON 4069 10556 4077 10521 4056 10516 4057 10552

$$
1 follow-up statement
869 
WGUS75 KBOU 070121
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
721 PM MDT FRI JUL 6 2012

COC069-070130-
/O.CAN.KBOU.FF.W.0012.000000T0000Z-120707T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LARIMER CO-
721 PM MDT FRI JUL 6 2012

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR CENTRAL LARIMER
COUNTY...

THE STORMS THAT PROMPTED THE WARNING HAS EXITED THE AREA. NO 
ADDITIONAL REPORTS OF FLOODING HAVE BEEN RECEIVED THEREFORE THE 
FLASH FLOOD WARNING HAS BEEN CANCELLED.

LAT...LON 4069 10556 4077 10521 4056 10516 4057 10552

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 6, 12:45 PM MDTAreal Flood AdvisoryBOULarimer90 min
Jul 6, 1:06 PM MDTFlash Flood WarningBOULarimer3 hr
Jul 6, 1:55 PM MDTAreal Flood AdvisoryBOUJefferson, Park80 min
Jul 6, 2:12 PM MDTAreal Flood AdvisoryBOULarimer93 min
Jul 6, 3:23 PM MDTAreal Flood AdvisoryBOUDouglas82 min
Jul 6, 3:36 PM MDTFlash Flood WarningBOUDouglas2 hr
Jul 6, 4:22 PM MDTAreal Flood AdvisoryBOULarimer83 min
Jul 6, 4:36 PM MDTAreal Flood AdvisoryBOUBoulder63 min
Jul 6, 4:52 PM MDTAreal Flood AdvisoryBOUDouglas83 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.