Alert archive / Colorado / Flash Flood Warnings in 2021
Flash Flood Warning 3, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this flash flood warning at Jun 5, 2021, 12:28 PM MDT for Larimer County, Colorado. It was in force for 98 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
- Jun 5, 2021, 12:28 PM MDT (18:28 UTC)
- Expired
- Jun 5, 2021, 2:06 PM MDT
- In force
- 98 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 18:31 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, 6.5 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 3372 m above ground
- 0-6 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- 27 m²/s²
- 0-3 km storm-relative helicity
- 51 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
727
WGUS55 KBOU 051828
FFWBOU
COC069-052130-
/O.NEW.KBOU.FF.W.0003.210605T1828Z-210605T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
1228 PM MDT Sat Jun 5 2021
The National Weather Service in Denver has issued a
* Flash Flood Warning for...
South Central Larimer County in north central Colorado...
* Until 330 PM MDT.
* At 1228 PM MDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. The expected rainfall rate is 1
inch in 30 minutes. 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, urban
areas, highways, streets and underpasses as well as
other poor drainage and low-lying areas.
* Some locations that will experience flash flooding include...
Glen Haven, Drake and Cedar Cove.
This includes the following additional locations...
Crystal Mountain, The Retreat and Storm Mountain.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Heavy Rainfall will cause minor flooding of creeks and streams,
roads and roadside culverts in the affected part of the Cameron Peak
burn area. The heavy rains could also trigger rock slides or debris
flows.
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 4055 10550 4053 10529 4040 10524 4039 10541
4045 10557 4050 10555
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1 INCH IN 30 MINUTES
$$
RJK2 follow-up statements
281
WGUS75 KBOU 051912
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
112 PM MDT Sat Jun 5 2021
COC069-052130-
/O.CON.KBOU.FF.W.0003.000000T0000Z-210605T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Larimer CO-
112 PM MDT Sat Jun 5 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 330 PM MDT THIS
AFTERNOON FOR SOUTH CENTRAL LARIMER COUNTY...
At 112 PM MDT, Doppler radar indicated showers and thunderstorms
continuing to producing light to moderate rainfall across the warned
area. Between 0.25 and 0.60 inches of rain have fallen. Flash
flooding may be occurring.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flash flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other poor
drainage and low-lying areas.
Some locations that will experience flash flooding include...
Glen Haven, Drake and Cedar Cove.
This includes the following additional locations...
Crystal Mountain, The Retreat and Storm Mountain.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Heavy Rainfall will cause minor flooding of creeks and streams,
roads and roadside culverts in the affected part of the Cameron Peak
burn area. The heavy rains could also trigger rock slides or debris
flows.
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 4055 10550 4053 10529 4040 10524 4039 10541
4045 10557 4050 10555
FLASH FLOOD...RADAR INDICATED
$$
RJK531
WGUS75 KBOU 052006
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
206 PM MDT Sat Jun 5 2021
COC069-052016-
/O.CAN.KBOU.FF.W.0003.000000T0000Z-210605T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Larimer CO-
206 PM MDT Sat Jun 5 2021
...FLASH FLOOD WARNING IS CANCELLED FOR SOUTH CENTRAL LARIMER
COUNTY...
The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.
LAT...LON 4055 10550 4053 10529 4040 10524 4039 10541
4045 10557 4050 10555
$$
RJKThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 5, 1:29 PM MDT | Areal Flood Advisory | BOU | Grand | 109 min |
| Jun 5, 1:59 PM MDT | Flash Flood Warning | BOU | Grand | 78 min |
| Jun 5, 2:43 PM MDT | Areal Flood Advisory | BOU | Grand | 2 hr |
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.