Alert archive / Colorado / Flash Flood Warnings in 2011

Flash Flood Warning 30, NWS Denver/Boulder, CO

July 18, 2011Summit County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 18, 2011, 7:25 PM MDT for Summit County, Colorado. It was in force for 95 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 18, 2011, 7:25 PM MDT (01:25 UTC)
Expired
Jul 18, 2011, 9:00 PM MDT
In force
95 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Flood severity
None

County Summit County, CO

The radar

The Denver radar (KFTG), 134 km from the middle of the area, began a volume at 01:27 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

Grand Junction, CO (KGJT), launched 00:00Z, 1.4 hours before the alert went out and 214 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, Grand Junction, CO at 00:00Z on 2011-07-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 11 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, Grand Junction, CO at 00:00Z on 2011-07-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -2 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
11 J/kg
Mixed-layer CIN
-245 J/kg
Mixed-layer LCL
2727 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
-2 m²/s²
0-3 km storm-relative helicity
44 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.

673 
WGUS55 KBOU 190125
FFWBOU
COC117-190300-
/O.NEW.KBOU.FF.W.0030.110719T0125Z-110719T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
725 PM MDT MON JUL 18 2011

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTH CENTRAL SUMMIT COUNTY IN CENTRAL COLORADO

* UNTIL 900 PM MDT

* AT 723 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM 2 MILES SOUTH OF BLUE RIVER...
  OR 61 MILES WEST OF DENVER. THIS STORM WAS MOVING NORTHWEST AT 15
  MPH.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  BRECKENRIDGE AND BLUE RIVER.

TRAINED WEATHER SPOTTERS REPORT NEARLY 2 INCHES OF RAIN HAS FALLEN 
IN THE LAST HOUR AT BRECKENRIDGE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF CREEKS 
AND STREAMS ESPECIALLY ALONG THE BLUE RIVER...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 3953 10612 3959 10601 3942 10597 3938 10608

$$
2 follow-up statements
985 
WGUS75 KBOU 190149
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
749 PM MDT MON JUL 18 2011

COC117-190300-
/O.CON.KBOU.FF.W.0030.000000T0000Z-110719T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUMMIT CO-
749 PM MDT MON JUL 18 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 900 PM MDT FOR SOUTH
CENTRAL SUMMIT COUNTY...

AT 746 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
MODERATE TO HEAVY RAIN CONTINUING NEAR BRECKENRIDGE...OR ABOUT 63 
MILES WEST OF DENVER. 

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
BRECKENRIDGE AND BLUE RIVER.

TRAINED WEATHER SPOTTERS REPORT 2.60 INCHES OF RAIN HAS FALLEN IN 
THE LAST HOUR IN BRECKENRIDGE. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING ALONG THE 
BLUE RIVER...CREEKS AND STREAMS ESPECIALLY SAWMILL...CUCUMBER AND 
ALONG FRENCH GULCH...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 3953 10612 3959 10601 3942 10597 3938 10608

$$
662 
WGUS75 KBOU 190223
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
823 PM MDT MON JUL 18 2011

COC117-190300-
/O.CON.KBOU.FF.W.0030.000000T0000Z-110719T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUMMIT CO-
823 PM MDT MON JUL 18 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 900 PM MDT FOR SOUTH
CENTRAL SUMMIT COUNTY...

AT 817 PM MDT...FLASH FLOODING WAS OCCURRING IN AND NEAR NEAR 
BRECKENRIDGE...OR ABOUT 60 MILES WEST OF DENVER.  ROCK SLIDES HAVE 
ALSO OCCURRED SOUTHEAST OF BRECKENRIDGE.  

LOCATIONS REMAINING IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
BRECKENRIDGE AND BLUE RIVER.

TRAINED WEATHER SPOTTERS REPORT NEARLY 3 INCHES OF RAIN HAS OCCURRED 
IN AND NEAR BRECKENRIDGE IN THE LAST 90 MINUTES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING ALONG THE 
BLUE RIVER...CREEKS AND STREAMS ESPECIALLY SAWMILL...CUCUMBER AND 
ALONG FRENCH GULCH...ROADS AND ROADSIDE CULVERTS. THE HEAVY RAINS 
WILL ALSO TRIGGER ROCK SLIDES AND 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 3953 10612 3959 10601 3942 10597 3938 10608

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 18, 6:08 PM MDTFlash Flood WarningBOULarimer2 hr
Jul 18, 6:57 PM MDTAreal Flood AdvisoryBOUSummit93 min
Jul 18, 7:29 PM MDTAreal Flood AdvisoryBOUSummit91 min
Jul 18, 8:30 PM MDTAreal Flood AdvisoryBOUPark2 hr
Jul 18, 8:52 PM MDTFlash Flood WarningBOUSummit113 min
Jul 18, 9:28 PM MDTAreal Flood AdvisoryBOUGrand24 hr
Jul 18, 10:52 PM MDTAreal Flood AdvisoryBOUSummit20 hr
Jul 19, 11:13 AM MDTFlash Flood WatchBOUBoulder, Clear Creek, Gilpin, Grand, Jackson, Jefferson and 3 more9 hr
Jul 19, 2:53 PM MDTSpecial Weather StatementBOUGilpin37 min
Jul 19, 3:27 PM MDTFlash Flood WarningBOUBoulder2 hr
Jul 19, 4:19 PM MDTSpecial Weather StatementBOUBroomfield26 min
Jul 19, 4:21 PM MDTAreal Flood AdvisoryBOUClear Creek, Gilpin, Jefferson, Park95 min
Jul 19, 4:58 PM MDTSpecial Weather StatementBOUBroomfield32 min
Jul 19, 5:09 PM MDTSpecial Weather StatementBOULarimer36 min
Jul 19, 5:11 PM MDTSevere Thunderstorm WarningBOUAdams, Weld49 min
Jul 19, 5:37 PM MDTSpecial Weather StatementBOUDenver23 min
Jul 19, 5:59 PM MDTSpecial Weather StatementBOUDenver31 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.