Alert archive / Colorado / Flash Flood Warnings in 2021
Flash Flood Warning 64, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this flash flood warning at Aug 2, 2021, 6:26 PM MDT for Larimer County, Colorado. It was in force for 116 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 2, 2021, 6:26 PM MDT (00:26 UTC)
- Expired
- Aug 2, 2021, 8:22 PM MDT
- In force
- 116 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
- Flood severity
- None
County Larimer County, CO
The radar
The Cheyenne radar (KCYS), 92 km from the middle of the area, began a volume at 00:28 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
Denver, CO (KDNR), launched 00:00Z, 0.4 hours before the alert went out and 217 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 3072 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- -25 m²/s²
- 0-3 km storm-relative helicity
- -57 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
751
WGUS55 KBOU 030026
FFWBOU
COC069-030330-
/O.NEW.KBOU.FF.W.0064.210803T0026Z-210803T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
626 PM MDT Mon Aug 2 2021
The National Weather Service in Denver has issued a
* Flash Flood Warning for...
Southwestern Larimer County in north central Colorado...
* Until 930 PM MDT.
* At 626 PM MDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 0.5 and 0.75 inches of
rain has fallen. Additional rainfall amounts up to 0.25 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...
Pingree Park.
This includes the following additional locations...
Poudre Springs and Sky Ranch.
This includes the following streams and drainages...
South Fork Cache La Poudre River, Pennock Creek, Little Beaver
Creek and Fall 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 affected part of the Cameron Peak burn area. Rock
slides or debris flows can also be expected across rural roads.
&&
LAT...LON 4062 10564 4061 10556 4056 10555 4055 10560
4055 10564
FLASH FLOOD...RADAR INDICATED
$$
RPK1 follow-up statement
912
WGUS75 KBOU 030222
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
822 PM MDT Mon Aug 2 2021
COC069-030232-
/O.CAN.KBOU.FF.W.0064.000000T0000Z-210803T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Larimer CO-
822 PM MDT Mon Aug 2 2021
...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHWESTERN LARIMER
COUNTY...
Flood waters have receded. The heavy rain has ended. Flooding is no
longer expected to pose a threat. Please continue to heed remaining
road closures.
A Flash Flood Watch remains in effect until 1000 PM MDT for Portions
of central and north central Colorado.
LAT...LON 4062 10564 4061 10556 4056 10555 4055 10560
4055 10564
$$
RPKThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 3, 3:41 AM MDT | Flash Flood Watch | BOU | Boulder, Clear Creek, Gilpin, Grand, Jackson, Jefferson and 3 more | 18 hr |
| Aug 3, 8:10 AM MDT | Areal Flood Advisory | BOU | Grand | 3 hr |
| Aug 3, 2:22 PM MDT | Areal Flood Advisory | BOU | Douglas, Jefferson | 113 min |
| Aug 3, 2:58 PM MDT | Flash Flood Warning | BOU | Elbert | 2 hr |
| Aug 3, 3:48 PM MDT | Areal Flood Advisory | BOU | Adams, Arapahoe, Elbert | 87 min |
| Aug 3, 4:05 PM MDT | Flash Flood Warning | BOU | Adams, Arapahoe | 115 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.