Alert archive / Colorado / Flash Flood Warnings in 2021
Flash Flood Warning 14, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this flash flood warning at Jul 1, 2021, 3:09 PM MDT for Larimer 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, 3:09 PM MDT (21:09 UTC)
- Expired
- Jul 1, 2021, 5:03 PM MDT
- In force
- 114 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
- Flood severity
- None
County Larimer County, CO
The radar
The Cheyenne radar (KCYS), 83 km from the middle of the area, began a volume at 21:08 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, 9.2 hours before the alert went out and 183 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
- 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
The text
As transmitted.
599
WGUS55 KBOU 012109
FFWBOU
COC069-012315-
/O.NEW.KBOU.FF.W.0014.210701T2109Z-210701T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
309 PM MDT Thu Jul 1 2021
The National Weather Service in Denver has issued a
* Flash Flood Warning for...
Southeastern Larimer County in north central Colorado...
* Until 515 PM MDT.
* At 309 PM MDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 0.5 and 1 inch of rain
has 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...
Masonville.
This includes the following streams and drainages...
Big Thompson River, Redstone Creek, Cedar Creek, Dry Creek, Indian
Creek and Buckhorn Creek.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
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 4051 10520 4045 10518 4042 10524 4046 10529
4051 10526
FLASH FLOOD...RADAR INDICATED
$$
RPK2 follow-up statements
501
WGUS75 KBOU 012153
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
353 PM MDT Thu Jul 1 2021
COC069-012315-
/O.CON.KBOU.FF.W.0014.000000T0000Z-210701T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Larimer CO-
353 PM MDT Thu Jul 1 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 515 PM MDT THIS
AFTERNOON FOR SOUTHEASTERN LARIMER COUNTY...
At 353 PM MDT, Doppler radar between 0.5 and 1 inch of rain has
fallen. Flash flooding is ongoing.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flash flooding of small creeks and streams, gulches,
roads, and poor drainage and low-lying areas.
Some locations that will experience flash flooding include...
Masonville.
This includes the following streams and drainages...
Big Thompson River, Redstone Creek, Cedar Creek, Dry Creek, Indian
Creek and Buckhorn Creek.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Heavy Rainfall will cause flash flooding of small creeks, streams,
and ditches in the affected part of the Cameron Peak burn area. Rock
slides or debris flows can also be expected across rural roads.
&&
LAT...LON 4051 10520 4045 10518 4042 10524 4046 10529
4051 10526
FLASH FLOOD...RADAR INDICATED
$$
RPK709
WGUS75 KBOU 012303
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
503 PM MDT Thu Jul 1 2021
COC069-012313-
/O.CAN.KBOU.FF.W.0014.000000T0000Z-210701T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Larimer CO-
503 PM MDT Thu Jul 1 2021
...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHEASTERN 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 1200 AM MDT Friday for
Portions of central, north central, and northeast Colorado.
LAT...LON 4051 10520 4045 10518 4042 10524 4046 10529
4051 10526
$$
RPKThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 30, 8:20 PM MDT | Areal Flood Advisory | BOU | Weld | 115 min |
| Jun 30, 8:50 PM MDT | Flash Flood Warning | BOU | Weld | 3 hr |
| Jun 30, 10:32 PM MDT | Flash Flood Warning | BOU | Weld | 3 hr |
| Jul 1, 12:56 AM MDT | Flash Flood Warning | BOU | Weld | 3 hr |
| Jul 1, 8:46 AM MDT | Flash Flood Watch | BOU | Adams, Arapahoe, Boulder, Broomfield, Clear Creek, Denver and 7 more | 12 hr |
| Jul 1, 11:27 AM MDT | Areal Flood Advisory | BOU | Elbert | 93 min |
| Jul 1, 11:49 AM MDT | Flash Flood Warning | BOU | Larimer | 116 min |
| Jul 1, 11:51 AM MDT | Areal Flood Advisory | BOU | Weld | 84 min |
| Jul 1, 12:13 PM MDT | Flash Flood Warning | BOU | Clear Creek, Gilpin | 86 min |
| Jul 1, 12:21 PM MDT | Areal Flood Advisory | BOU | Elbert | 114 min |
| Jul 1, 12:24 PM MDT | Flash Flood Warning | BOU | Weld | 2 hr |
| Jul 1, 12:28 PM MDT | Areal Flood Advisory | BOU | Weld | 92 min |
| Jul 1, 12:30 PM MDT | Special Weather Statement | BOU | Adams | 30 min |
| Jul 1, 12:56 PM MDT | Special Weather Statement | BOU | Adams | 34 min |
| Jul 1, 12:58 PM MDT | Areal Flood Advisory | BOU | Grand | 92 min |
| Jul 1, 1:05 PM MDT | Areal Flood Advisory | BOU | Adams, Weld | 85 min |
| Jul 1, 1:12 PM MDT | Areal Flood Advisory | BOU | Weld | 93 min |
| Jul 1, 1:25 PM MDT | Areal Flood Advisory | BOU | Douglas | 95 min |
| Jul 1, 1:28 PM MDT | Flash Flood Warning | BOU | Weld | 2 hr |
| Jul 1, 1:33 PM MDT | Areal Flood Advisory | BOU | Grand | 87 min |
| Jul 1, 1:55 PM MDT | Areal Flood Advisory | BOU | Elbert | 95 min |
| Jul 1, 2:20 PM MDT | Areal Flood Advisory | BOU | Adams, Arapahoe | 3 hr |
| Jul 1, 2:24 PM MDT | Special Weather Statement | BOU | Arapahoe | 21 min |
| Jul 1, 2:26 PM MDT | Severe Thunderstorm Warning | BOU | Arapahoe | 34 min |
| Jul 1, 2:52 PM MDT | Areal Flood Advisory | BOU | Boulder, Larimer | 83 min |
| Jul 1, 3:04 PM MDT | Areal Flood Advisory | BOU | Arapahoe | 86 min |
| Jul 1, 3:17 PM MDT | Areal Flood Advisory | BOU | Boulder | 88 min |
| Jul 1, 3:21 PM MDT | Flash Flood Warning | BOU | Arapahoe | 114 min |
| Jul 1, 3:36 PM MDT | Special Weather Statement | BOU | Boulder | 24 min |
| Jul 1, 3:51 PM MDT | Areal Flood Advisory | BOU | Larimer | 84 min |
| Jul 1, 3:55 PM MDT | Areal Flood Advisory | BOU | Arapahoe, Denver | 95 min |
| Jul 1, 4:03 PM MDT | Areal Flood Advisory | BOU | Boulder | 87 min |
| Jul 1, 4:27 PM MDT | Areal Flood Advisory | BOU | Jefferson | 93 min |
| Jul 1, 4:36 PM MDT | Flash Flood Warning | BOU | Jefferson | 84 min |
| Jul 1, 4:42 PM MDT | Areal Flood Advisory | BOU | Larimer | 93 min |
| Jul 1, 5:19 PM MDT | Areal Flood Advisory | BOU | Park | 86 min |
| Jul 1, 5:57 PM MDT | Areal Flood Advisory | BOU | Jefferson, Park | 93 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.