Alert archive / Colorado / Flash Flood Warnings in 2021

Flash Flood Warning 11, NWS Denver/Boulder, CO

July 1, 2021Clear Creek County, Gilpin County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jul 1, 2021, 12:13 PM MDT for Clear Creek County, Gilpin County, Colorado. It was in force for 86 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 1, 2021, 12:13 PM MDT (18:13 UTC)
Expired
Jul 1, 2021, 1:39 PM MDT
In force
86 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), 86 km from the middle of the area, began a volume at 18:14 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, 6.2 hours before the alert went out and 199 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 2021-07-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 240 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 2021-07-01The 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
240 J/kg
Mixed-layer CIN
-180 J/kg
Mixed-layer LCL
1308 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
17 m²/s²
0-3 km storm-relative helicity
9 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

242 
WGUS55 KBOU 011813
FFWBOU
COC019-047-012015-
/O.NEW.KBOU.FF.W.0011.210701T1813Z-210701T2015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
1213 PM MDT Thu Jul 1 2021

The National Weather Service in Denver has issued a

* Flash Flood Warning for...
  Northeastern Clear Creek County in central Colorado...
  South Central Gilpin County in central Colorado...

* Until 215 PM MDT.

* At 1213 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Flash flooding is ongoing or 
  expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, gulches,
           roads, and poor drainage and low-lying areas,
           including Virginia Canyon.

* Some locations that will experience flash flooding include...
  Idaho Springs, Central City, Black Hawk, Dumont and Russell Gulch.

This includes the following streams and drainages...
  Mill Creek, Fall River, Clear Creek, North Clear Creek, Chicago 
  Creek, Barbour Fork, Little Bear Creek and Soda Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

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.

&&

LAT...LON 3980 10560 3980 10557 3981 10548 3972 10549
      3972 10560

FLASH FLOOD...RADAR INDICATED

$$

RPK
2 follow-up statements
614 
WGUS75 KBOU 011849
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
1249 PM MDT Thu Jul 1 2021

COC019-047-012015-
/O.CON.KBOU.FF.W.0011.000000T0000Z-210701T2015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clear Creek CO-Gilpin CO-
1249 PM MDT Thu Jul 1 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 215 PM MDT THIS 
AFTERNOON FOR NORTHEASTERN CLEAR CREEK AND SOUTH CENTRAL GILPIN 
COUNTIES...

At 1249 PM MDT, Doppler radar indicated thunderstorms producing 
heavy rain across the warned area. Flash flooding is ongoing or 
expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, gulches,
         roads, and poor drainage and low-lying areas, including
         Virginia Canyon.

Some locations that will experience flash flooding include...
  Idaho Springs, Central City, Black Hawk, Dumont and Russell Gulch.

This includes the following streams and drainages...
  Mill Creek, Fall River, Clear Creek, North Clear Creek, Chicago 
  Creek, Barbour Fork, Little Bear Creek and Soda Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

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.

&&

LAT...LON 3980 10560 3980 10557 3981 10548 3972 10549
      3972 10560

FLASH FLOOD...RADAR INDICATED

$$

RPK
078 
WGUS75 KBOU 011939
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
139 PM MDT Thu Jul 1 2021

COC019-047-011949-
/O.CAN.KBOU.FF.W.0011.000000T0000Z-210701T2015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clear Creek CO-Gilpin CO-
139 PM MDT Thu Jul 1 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHEASTERN CLEAR CREEK AND 
SOUTH CENTRAL GILPIN COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

A Flash Flood Watch remains in effect until 1200 AM MDT Friday for 
Portions of central, north central, and northeast Colorado.

LAT...LON 3980 10560 3980 10557 3981 10548 3972 10549
      3972 10560

$$

RPK

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 30, 8:20 PM MDTAreal Flood AdvisoryBOUWeld115 min
Jun 30, 8:50 PM MDTFlash Flood WarningBOUWeld3 hr
Jun 30, 10:32 PM MDTFlash Flood WarningBOUWeld3 hr
Jul 1, 12:56 AM MDTFlash Flood WarningBOUWeld3 hr
Jul 1, 8:46 AM MDTFlash Flood WatchBOUAdams, Arapahoe, Boulder, Broomfield, Clear Creek, Denver and 7 more12 hr
Jul 1, 11:27 AM MDTAreal Flood AdvisoryBOUElbert93 min
Jul 1, 11:49 AM MDTFlash Flood WarningBOULarimer116 min
Jul 1, 11:51 AM MDTAreal Flood AdvisoryBOUWeld84 min
Jul 1, 12:21 PM MDTAreal Flood AdvisoryBOUElbert114 min
Jul 1, 12:24 PM MDTFlash Flood WarningBOUWeld2 hr
Jul 1, 12:28 PM MDTAreal Flood AdvisoryBOUWeld92 min
Jul 1, 12:30 PM MDTSpecial Weather StatementBOUAdams30 min
Jul 1, 12:56 PM MDTSpecial Weather StatementBOUAdams34 min
Jul 1, 12:58 PM MDTAreal Flood AdvisoryBOUGrand92 min
Jul 1, 1:05 PM MDTAreal Flood AdvisoryBOUAdams, Weld85 min
Jul 1, 1:12 PM MDTAreal Flood AdvisoryBOUWeld93 min
Jul 1, 1:25 PM MDTAreal Flood AdvisoryBOUDouglas95 min
Jul 1, 1:28 PM MDTFlash Flood WarningBOUWeld2 hr
Jul 1, 1:33 PM MDTAreal Flood AdvisoryBOUGrand87 min
Jul 1, 1:55 PM MDTAreal Flood AdvisoryBOUElbert95 min
Jul 1, 2:20 PM MDTAreal Flood AdvisoryBOUAdams, Arapahoe3 hr
Jul 1, 2:24 PM MDTSpecial Weather StatementBOUArapahoe21 min
Jul 1, 2:26 PM MDTSevere Thunderstorm WarningBOUArapahoe34 min
Jul 1, 2:52 PM MDTAreal Flood AdvisoryBOUBoulder, Larimer83 min
Jul 1, 3:04 PM MDTAreal Flood AdvisoryBOUArapahoe86 min
Jul 1, 3:09 PM MDTFlash Flood WarningBOULarimer114 min
Jul 1, 3:17 PM MDTAreal Flood AdvisoryBOUBoulder88 min
Jul 1, 3:21 PM MDTFlash Flood WarningBOUArapahoe114 min
Jul 1, 3:36 PM MDTSpecial Weather StatementBOUBoulder24 min
Jul 1, 3:51 PM MDTAreal Flood AdvisoryBOULarimer84 min
Jul 1, 3:55 PM MDTAreal Flood AdvisoryBOUArapahoe, Denver95 min
Jul 1, 4:03 PM MDTAreal Flood AdvisoryBOUBoulder87 min
Jul 1, 4:27 PM MDTAreal Flood AdvisoryBOUJefferson93 min
Jul 1, 4:36 PM MDTFlash Flood WarningBOUJefferson84 min
Jul 1, 4:42 PM MDTAreal Flood AdvisoryBOULarimer93 min
Jul 1, 5:19 PM MDTAreal Flood AdvisoryBOUPark86 min
Jul 1, 5:57 PM MDTAreal Flood AdvisoryBOUJefferson, Park93 min

Nearby

Flash Flood Warnings in Colorado, 2021Every flash flood warning in 2021

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.