Alert archive / Colorado / Flash Flood Warnings in 2011

Flash Flood Warning 9, NWS Denver/Boulder, CO

July 7, 2011Clear Creek County, Gilpin County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 7, 2011, 8:02 PM MDT for Clear Creek County, Gilpin County, Colorado. It was in force for 97 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 7, 2011, 8:02 PM MDT (02:02 UTC)
Expired: Jul 7, 2011, 9:39 PM MDT
In force: 97 min
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), 84 km from the middle of the area, began a volume at 02:04 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, 2.0 hours before the alert went out and 197 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 259 J/kg
Mixed-layer CIN: -60 J/kg
Mixed-layer LCL: 1195 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 58 m²/s²
0-3 km storm-relative helicity: 88 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

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

208 
WGUS55 KBOU 080202
FFWBOU
COC019-047-080400-
/O.NEW.KBOU.FF.W.0009.110708T0202Z-110708T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE DENVER CO
802 PM MDT THU JUL 7 2011

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

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

* UNTIL 1000 PM MDT

* AT 759 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  THUNDERSTORM PRODUCING HEAVY RAIN WILL BE MOVING ACROSS THE        
  VIRGINIA CANYON AREA OVER NORTHEASTERN CLEAR CREEK COUNTY...OR 30   
  MILES WEST OF DENVER. THE STORMS WERE MOVING EAST AT 15 MPH.

* THE STORM PRODUCING VERY HEAVY RAIN WILL REMAIN OVER VIRGINIA      
  CANYON WHERE UP TO 1 INCH OF RAIN COULD FALL IN LESS THAN 30       
  MINUTES.

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 THESE STORMS 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.

&&

LAT...LON 3978 10554 3976 10550 3974 10551 3977 10555

$$

1 follow-up statement

279 
WGUS75 KBOU 080339
FFSBOU

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
939 PM MDT THU JUL 7 2011

COC019-047-080347-
/O.CAN.KBOU.FF.W.0009.000000T0000Z-110708T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GILPIN CO-CLEAR CREEK CO-
939 PM MDT THU JUL 7 2011

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR NORTHEASTERN CLEAR
CREEK AND EXTREME SOUTH CENTRAL GILPIN COUNTIES...

THE STORM THAT PROMPTED THE WARNING HAS EXITED THE AREA. LOCAL 
DISPATCH IN CLEAR CREEK COUNTY REPORTED NO FLOODING IN THE VIRGINA 
CANYON. 

THERE WILL BE CONTINUED SHOWERS AND A FEW THUNDERSTORMS THROUGH 
MIDNIGHT BUT OVERALL RAINFALL RATES WILL BE UNDER A QUARTER INCH PER 
HOUR. 

LAT...LON 3978 10554 3976 10550 3974 10551 3977 10555

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 7, 6:07 PM MDT	Areal Flood Advisory	BOU	Boulder, Gilpin, Jefferson	83 min
Jul 7, 6:18 PM MDT	Flash Flood Warning	BOU	Boulder	3 hr
Jul 7, 6:27 PM MDT	Flash Flood Warning	BOU	Boulder, Gilpin, Jefferson	3 hr
Jul 7, 6:35 PM MDT	Areal Flood Advisory	BOU	Larimer	85 min
Jul 7, 7:28 PM MDT	Areal Flood Advisory	BOU	Boulder	2 hr
Jul 7, 7:38 PM MDT	Areal Flood Advisory	BOU	Adams, Arapahoe, Denver	2 hr
Jul 7, 10:05 PM MDT	Areal Flood Advisory	BOU	Adams, Arapahoe, Denver	4 hr
Jul 7, 10:27 PM MDT	River Flood Advisory	BOU	Adams	14 hr
Jul 8, 1:21 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Broomfield, Denver, Jefferson	39 min
Jul 8, 1:46 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Denver	44 min
Jul 8, 2:07 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Arapahoe, Denver	34 min
Jul 8, 4:11 PM MDT	Severe Thunderstorm Warning	BOU	Elbert, Lincoln	49 min
Jul 8, 4:39 PM MDT	Severe Thunderstorm Warning	BOU	Larimer, Weld	24 min
Jul 8, 4:57 PM MDT	Severe Thunderstorm Warning	BOU	Lincoln	16 min
Jul 8, 5:11 PM MDT	Severe Thunderstorm Warning	BOU	Elbert	21 min
Jul 8, 5:20 PM MDT	Areal Flood Advisory	BOU	Summit	4 days

Nearby

Flash Flood Warnings in Colorado, 2011 Every 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.