Alert archive / Colorado / Flash Flood Warnings in 2011

Flash Flood Warning 27, NWS Denver/Boulder, CO

July 17, 2011Clear Creek County, Gilpin County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 17, 2011, 2:57 PM MDT for Clear Creek County, Gilpin 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 17, 2011, 2:57 PM MDT (20:57 UTC)
Expired
Jul 17, 2011, 6:00 PM MDT
In force
3 hr
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Flood severity
None

Counties Clear Creek County, CO, Gilpin County, CO

The radar

The Denver radar (KFTG), 89 km from the middle of the area, began a volume at 20:57 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, 9.0 hours before the alert went out and 202 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 2011-07-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 94 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 2011-07-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 17 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
94 J/kg
Mixed-layer CIN
-352 J/kg
Mixed-layer LCL
1885 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
17 m²/s²
0-3 km storm-relative helicity
22 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.

753 
WGUS55 KBOU 172057
FFWBOU
COC019-047-180000-
/O.NEW.KBOU.FF.W.0027.110717T2057Z-110718T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
257 PM MDT SUN JUL 17 2011

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL GILPIN COUNTY IN CENTRAL COLORADO
  EXTREME NORTH CENTRAL CLEAR CREEK COUNTY IN CENTRAL COLORADO

* UNTIL 600 PM MDT

* AT 256 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM 4 MILES SOUTH OF TOLLAND...OR
  35 MILES WEST OF DENVER. THIS STORM WAS MOVING NORTH AT 10 MPH.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO TOLLAND AND
  DUMONT.

DOPPLER RADAR ESTIMATES OVER TWO INCHES OF RAIN HAS FALLEN IN THE 
LAST 45 MINUTES OVER NORTH CENTRAL CLEAR CREEK AND CENTRAL GILPIN
COUNTIES. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 STEEP TERRAIN.

IT IS IMPORTANT TO KNOW WHERE YOU ARE RELATIVE TO STREAMS...RIVERS...
OR CREEKS...WHICH CAN BECOME KILLERS IN HEAVY RAINS. CAMPERS SHOULD
AVOID CAMPING ALONG STREAMS OR CREEKS DURING THREATENING RAINS.

&&

LAT...LON 3993 10563 3993 10551 3979 10553 3979 10556
      3978 10558 3979 10558 3978 10559 3978 10563
      3979 10563 3979 10564

$$
3 follow-up statements
335 
WGUS75 KBOU 172132
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
332 PM MDT SUN JUL 17 2011

COC019-047-180000-
/O.CON.KBOU.FF.W.0027.000000T0000Z-110718T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GILPIN CO-CLEAR CREEK CO-
332 PM MDT SUN JUL 17 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 600 PM MDT FOR
EXTREME NORTH CENTRAL CLEAR CREEK AND WESTERN GILPIN COUNTIES...

AT 330 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THUNDERSTORMS WITH HEAVY RAIN REDEVELOPING OVER NORTH CENTRAL CLEAR 
CREEK COUNTY. THESE STORMS WERE MOVING NORTH AT 10 MPH.

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
TOLLAND AND DUMONT.

DOPPLER RADAR ESTIMATES THAT UP TO THREE INCHES OF RAIN MAY HAVE 
FALLEN OVER CENTRAL GILPIN COUNTY IN THE LAST HOUR.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 STEEP TERRAIN.

IT IS IMPORTANT TO KNOW WHERE YOU ARE RELATIVE TO STREAMS...RIVERS...
OR CREEKS...WHICH CAN BECOME KILLERS IN HEAVY RAINS. CAMPERS SHOULD
AVOID CAMPING ALONG STREAMS OR CREEKS DURING THREATENING RAINS.

&&

LAT...LON 3993 10563 3993 10551 3979 10553 3979 10556
      3978 10558 3979 10558 3978 10559 3978 10563
      3979 10563 3979 10564

$$
944 
WGUS75 KBOU 172219
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
419 PM MDT SUN JUL 17 2011

COC019-047-180000-
/O.CON.KBOU.FF.W.0027.000000T0000Z-110718T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GILPIN CO-CLEAR CREEK CO-
419 PM MDT SUN JUL 17 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 600 PM MDT FOR
EXTREME NORTH CENTRAL CLEAR CREEK AND WESTERN GILPIN COUNTIES...

AT 417 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
MODERATE TO HEAVY RAIN FROM THUNDERSTORMS FROM NORTH CENTRAL CLEAR 
CREEK INTO CENTRAL GILPIN COUNTIES. THE STORMS WERE MOVING 
NORTH AT 15 MPH.

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
TOLLAND AND DUMONT.

DOPPLER RADAR ESTIMATES THAT AROUND 3 INCHES OF RAIN MAY HAVE FALLEN 
THIS AFTERNOON OVER PORTIONS OF CENTRAL GILPIN COUNTY NEAR TOLLAND.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 STEEP TERRAIN.

IT IS IMPORTANT TO KNOW WHERE YOU ARE RELATIVE TO STREAMS...RIVERS...
OR CREEKS...WHICH CAN BECOME KILLERS IN HEAVY RAINS. CAMPERS SHOULD
AVOID CAMPING ALONG STREAMS OR CREEKS DURING THREATENING RAINS.

&&

LAT...LON 3993 10563 3993 10551 3979 10553 3979 10556
      3978 10558 3979 10558 3978 10559 3978 10563
      3979 10563 3979 10564

$$
852 
WGUS75 KBOU 172355
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
555 PM MDT SUN JUL 17 2011

COC019-047-180005-
/O.EXP.KBOU.FF.W.0027.000000T0000Z-110718T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GILPIN CO-CLEAR CREEK CO-
555 PM MDT SUN JUL 17 2011

...THE FLASH FLOOD WARNING WILL EXPIRE AT 600 PM MDT FOR EXTREME
NORTH CENTRAL CLEAR CREEK AND WESTERN GILPIN COUNTIES...

FLOOD WATERS HAVE SUBSIDED AND FLASH FLOODING IS NO LONGER EXPECTED.

LAT...LON 3993 10563 3993 10551 3979 10553 3979 10556
      3978 10558 3979 10558 3978 10559 3978 10563
      3979 10563 3979 10564

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 16, 6:33 PM MDTRiver Flood AdvisoryBOUMorgan40 hr
Jul 16, 6:33 PM MDTRiver Flood AdvisoryBOULogan, Morgan, Washington63 hr
Jul 16, 9:37 PM MDTSevere Thunderstorm WarningBOUWeld35 min
Jul 17, 12:55 PM MDTAreal Flood AdvisoryBOUBoulder, Grand, Larimer80 min
Jul 17, 2:20 PM MDTSpecial Weather StatementBOUGilpin25 min
Jul 17, 2:25 PM MDTSevere Thunderstorm WarningBOUGilpin35 min
Jul 17, 2:29 PM MDTAreal Flood AdvisoryBOUClear Creek, Gilpin91 min
Jul 17, 3:33 PM MDTSpecial Weather StatementBOUBoulder27 min
Jul 17, 3:37 PM MDTAreal Flood AdvisoryBOUBoulder83 min
Jul 17, 3:44 PM MDTFlash Flood WarningBOUBoulder3 hr
Jul 17, 3:59 PM MDTSpecial Weather StatementBOUBoulder31 min
Jul 17, 4:16 PM MDTAreal Flood AdvisoryBOUBoulder89 min
Jul 17, 4:31 PM MDTSpecial Weather StatementBOUBoulder29 min
Jul 17, 4:57 PM MDTSpecial Weather StatementBOUBoulder33 min
Jul 17, 5:01 PM MDTAreal Flood AdvisoryBOUBoulder89 min
Jul 17, 5:25 PM MDTSpecial Weather StatementBOUBoulder35 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.