Alert archive / Colorado / Flash Flood Warnings in 2021
Flash Flood Warning 17, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this flash flood warning at Jul 1, 2021, 6:21 PM MDT for Jefferson County, Park County, Colorado. It was in force for 114 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, 6:21 PM MDT (00:21 UTC)
- Expired
- Jul 1, 2021, 8:15 PM MDT
- In force
- 114 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
- Flood severity
- None
Counties Jefferson County, CO, Park County, CO
The radar
The Denver radar (KFTG), 91 km from the middle of the area, began a volume at 00:20 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, 0.4 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.
- Mixed-layer CAPE
- 13 J/kg
- Mixed-layer CIN
- -50 J/kg
- Mixed-layer LCL
- 1238 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- -8 m²/s²
- 0-3 km storm-relative helicity
- -43 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
681
WGUS55 KBOU 020021
FFWBOU
COC059-093-020215-
/O.NEW.KBOU.FF.W.0017.210702T0021Z-210702T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
621 PM MDT Thu Jul 1 2021
The National Weather Service in Denver has issued a
* Flash Flood Warning for...
West Central Jefferson County in central Colorado...
Northeastern Park County in central Colorado...
* Until 815 PM MDT.
* At 621 PM MDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 2 and 3 inches of rain
have fallen. 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.
* Some locations that will experience flash flooding include...
Bailey, Shawnee and Glenisle.
This includes the following streams and drainages...
North Fork South Platte River, Buffalo Creek, South Fork Lost
Creek, Elk Creek, Craig Creek, Freeman Creek, Deer Creek, Wisp
Creek, Crow Creek and Rock 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 3944 10558 3947 10540 3938 10533 3933 10540
3932 10542 3935 10557
FLASH FLOOD...RADAR INDICATED
$$
RPK2 follow-up statements
617
WGUS75 KBOU 020109
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
709 PM MDT Thu Jul 1 2021
COC059-093-020215-
/O.CON.KBOU.FF.W.0017.000000T0000Z-210702T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson CO-Park CO-
709 PM MDT Thu Jul 1 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 PM MDT THIS
EVENING FOR WEST CENTRAL JEFFERSON AND NORTHEASTERN PARK COUNTIES...
At 709 PM MDT, Doppler radar indicated between 2 and 3 inches of
rain have fallen. Flash flooding is ongoing or expected to begin
shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flash flooding of small creeks and streams, gulches,
roads, and poor drainage and low-lying areas.
Some locations that will experience flash flooding include...
Bailey, Shawnee and Glenisle.
This includes the following streams and drainages...
North Fork South Platte River, Buffalo Creek, South Fork Lost
Creek, Elk Creek, Craig Creek, Freeman Creek, Deer Creek, Wisp
Creek, Crow Creek and Rock Creek.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Excessive runoff from this storm will cause flash flooding of creeks
and streams, roads and roadside culverts. The heavy rains could also
trigger rock slides or debris flows in steep terrain.
&&
LAT...LON 3944 10558 3947 10540 3938 10533 3933 10540
3932 10542 3935 10557
FLASH FLOOD...RADAR INDICATED
$$
RPK502
WGUS75 KBOU 020213
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
813 PM MDT Thu Jul 1 2021
COC059-093-020223-
/O.EXP.KBOU.FF.W.0017.000000T0000Z-210702T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jefferson CO-Park CO-
813 PM MDT Thu Jul 1 2021
...FLASH FLOOD WARNING WILL EXPIRE AT 815 PM MDT THIS EVENING FOR
WEST CENTRAL JEFFERSON AND NORTHEASTERN PARK COUNTIES...
Flooding is no longer expected to pose a threat. Please continue to
heed remaining road closures.
LAT...LON 3944 10558 3947 10540 3938 10533 3933 10540
3932 10542 3935 10557
$$
SchlatterThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 1, 6:48 PM MDT | Areal Flood Advisory | BOU | Arapahoe, Elbert | 87 min |
| Jul 1, 6:52 PM MDT | Areal Flood Advisory | BOU | Weld | 83 min |
| Jul 2, 1:37 PM MDT | Areal Flood Advisory | BOU | Grand | 67 min |
| Jul 2, 2:26 PM MDT | Areal Flood Advisory | BOU | Larimer | 2 hr |
| Jul 2, 3:26 PM MDT | Areal Flood Advisory | BOU | Larimer | 59 min |
| Jul 2, 3:37 PM MDT | Areal Flood Advisory | BOU | Park | 63 min |
| Jul 2, 5:13 PM MDT | Special Weather Statement | BOU | Jefferson | 32 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.