Alert archive / Colorado / Flash Flood Warnings in 2011

Flash Flood Warning 31, NWS Denver/Boulder, CO

July 18, 2011Summit County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 18, 2011, 8:52 PM MDT for Summit County, Colorado. It was in force for 113 min. 1 report 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
Jul 18, 2011, 8:52 PM MDT (02:52 UTC)
Expired
Jul 18, 2011, 10:45 PM MDT
In force
113 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Flood severity
None

County Summit County, CO

The radar

The Denver radar (KFTG), 132 km from the middle of the area, began a volume at 02:54 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
Jul 18, 9:15 PM MDTHEAVY RAIN 3.59Breckenridge, COEAST SIDE OF BRECKENRIDGE

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Grand Junction, CO (KGJT), launched 00:00Z, 2.9 hours before the alert went out and 216 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°0°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.

955 
WGUS55 KBOU 190252
FFWBOU
COC117-190445-
/O.NEW.KBOU.FF.W.0031.110719T0252Z-110719T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
852 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 1045 PM MDT

* AT 849 PM MDT...FLASH FLOODING WAS OCCURRING FROM BLUE RIVER TO 
BRECKENRIDGE AND MAY EVENTUALLY EXTEND NORTHWARD ALONG THE BLUE 
RIVER TO SOUTH OF DILLON

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

TRAINED WEATHER SPOTTERS REPORTED UP TO 3 INCHES OF RAIN HAS 
OCCURRED 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 
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 3956 10608 3961 10603 3959 10598 3942 10597
      3937 10604 3938 10608

$$
2 follow-up statements
788 
WGUS75 KBOU 190322
FFSBOU

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

COC117-190445-
/O.CON.KBOU.FF.W.0031.000000T0000Z-110719T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUMMIT CO-
922 PM MDT MON JUL 18 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1045 PM MDT FOR
SOUTH CENTRAL SUMMIT COUNTY...

FLASH FLOODING WAS OCCURRING FROM BLUE RIVER TO BRECKENRIDGE AND MAY 
EVENTUALLY EXTEND NORTHWARD ALONG THE BLUE RIVER TO SOUTH OF DILLON

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

TRAINED WEATHER SPOTTERS REPORTED 3.60 INCHES OF RAIN HAS OCCURRED 
IN BRECKENRIDGE THIS EVENING. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING ALONG THE 
BLUE AND SWAN RIVERS...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 3956 10608 3961 10603 3959 10598 3942 10597
      3937 10604 3938 10608

$$
176 
WGUS75 KBOU 190454
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
1054 PM MDT MON JUL 18 2011

COC117-190503-
/O.EXP.KBOU.FF.W.0031.000000T0000Z-110719T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUMMIT CO-
1054 PM MDT MON JUL 18 2011

...THE FLASH FLOOD WARNING HAS EXPIRED FOR SOUTH CENTRAL SUMMIT
COUNTY...

FLASH FLOODING IS NO LONGER EXPECTED. HOWEVER...RIVERS...CREEKS AND 
STREAMS WILL CONTINUE TO RUN HIGH THROUGH SUMMIT INTO TUESDAY 
MORNING. A SMALL STREAM FLOOD ADVISORY IS IN EFFECT THROUGH 1045 AM 
MDT TUESDAY MORNING FOR SOUTHERN SUMMIT COUNTY. 

LAT...LON 3956 10608 3961 10603 3959 10598 3942 10597
      3937 10604 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, 7:25 PM MDTFlash Flood WarningBOUSummit95 min
Jul 18, 7:29 PM MDTAreal Flood AdvisoryBOUSummit91 min
Jul 18, 8:30 PM MDTAreal Flood AdvisoryBOUPark2 hr
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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.