Alert archive / Colorado / Flash Flood Warnings in 2021
Flash Flood Warning 73, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this flash flood warning at Aug 16, 2021, 4:24 PM MDT for Grand County, Colorado. It was in force for 111 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
- Aug 16, 2021, 4:24 PM MDT (22:24 UTC)
- Expired
- Aug 16, 2021, 6:15 PM MDT
- In force
- 111 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
- Flood severity
- None
County Grand County, CO
The radar
The Denver radar (KFTG), 143 km from the middle of the area, began a volume at 22:28 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 12:00Z, 10.4 hours before the alert went out and 231 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
- 25 J/kg
- Mixed-layer CIN
- -229 J/kg
- Mixed-layer LCL
- 2786 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- -1 m²/s²
- 0-3 km storm-relative helicity
- 91 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
777
WGUS55 KBOU 162224
FFWBOU
COC049-170015-
/O.NEW.KBOU.FF.W.0073.210816T2224Z-210817T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
424 PM MDT Mon Aug 16 2021
The National Weather Service in Denver has issued a
* Flash Flood Warning for...
Central Grand County in north central Colorado...
* Until 615 PM MDT.
* At 424 PM MDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Up to 0.5 inches of rain have
fallen. Additional rainfall amounts up to 0.5 inches are possible
in 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.
* Some locations that will experience flash flooding include...
mainly rural areas of Central Grand County
This includes the following streams and drainages...
Smith Creek, North Fork Cabin Creek, East Fork Troublesome Creek,
Wheatley Creek, Colorado River, Drowsy Water Creek, Kinney Creek
and Corral Creek.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Move to higher ground now. Act quickly to protect your life.
Heavy Rainfall will cause flash flooding of small creeks, streams,
and ditches in the East Troublesome burn area. Rock slides or debris
flows can also be expected across rural roads.
&&
LAT...LON 4019 10610 4012 10612 4011 10613 4011 10616
4013 10619 4016 10622 4019 10622
FLASH FLOOD...RADAR INDICATED
$$
RPK1 follow-up statement
882
WGUS75 KBOU 170013
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
613 PM MDT Mon Aug 16 2021
COC049-170023-
/O.EXP.KBOU.FF.W.0073.000000T0000Z-210817T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Grand CO-
613 PM MDT Mon Aug 16 2021
...FLASH FLOOD WARNING WILL EXPIRE AT 615 PM MDT THIS EVENING FOR
CENTRAL GRAND COUNTY...
The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.
LAT...LON 4019 10610 4012 10612 4011 10613 4011 10616
4013 10619 4016 10622 4019 10622
$$
RPKThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 15, 6:16 PM MDT | Special Weather Statement | BOU | Lincoln | 59 min |
| Aug 16, 3:53 PM MDT | Flash Flood Warning | BOU | Jackson, Larimer | 112 min |
| Aug 16, 4:06 PM MDT | Areal Flood Advisory | BOU | Grand | 18 min |
| Aug 16, 4:32 PM MDT | Flash Flood Warning | BOU | Larimer | 118 min |
| Aug 16, 5:02 PM MDT | Areal Flood Advisory | BOU | Grand | 88 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.