Alert archive / Colorado / Flash Flood Warnings in 2021
Flash Flood Warning 1, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this flash flood warning at May 2, 2021, 4:07 PM MDT for Larimer County, Colorado. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- May 2, 2021, 4:07 PM MDT (22:07 UTC)
- Expired
- May 2, 2021, 7:00 PM MDT
- In force
- 3 hr
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
- Flood severity
- None
County Larimer County, CO
The radar
The Cheyenne radar (KCYS), 87 km from the middle of the area, began a volume at 22:11 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, 10.1 hours before the alert went out and 219 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
- 1976 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- -89 m²/s²
- 0-3 km storm-relative helicity
- 10 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
340
WGUS55 KBOU 022207
FFWBOU
COC069-030100-
/O.NEW.KBOU.FF.W.0001.210502T2207Z-210503T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
407 PM MDT Sun May 2 2021
The National Weather Service in Denver has issued a
* Flash Flood Warning for...
Central Larimer County in north central Colorado...
* Until 700 PM MDT.
* At 407 PM MDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Flash flooding is ongoing or
expected to begin shortly.
Excessive rainfall over the burn area will result in debris flows.
The debris flows can consist of rock, mud, vegetation and other
loose materials.
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...
mainly rural areas of Central Larimer County
This includes the following additional locations...
Jacks Gulch, Lower Pingree Park Road and Crown Point Road.
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 4064 10566 4066 10567 4069 10556 4068 10550
4062 10551 4060 10562
FLASH FLOOD...RADAR INDICATED
$$
Meier1 follow-up statement
236
WGUS75 KBOU 030053
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
653 PM MDT Sun May 2 2021
COC069-030103-
/O.EXP.KBOU.FF.W.0001.000000T0000Z-210503T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Calwood Burn Area Larimer County
653 PM MDT Sun May 2 2021
...FLASH FLOOD WARNING WILL EXPIRE AT 7 PM MDT THIS EVENING FOR
CENTRAL LARIMER COUNTY...
The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.
LAT...LON 4064 10566 4066 10567 4069 10556 4068 10550
4062 10551 4060 10562
$$
MeierThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 1, 7:40 PM MDT | Special Weather Statement | BOU | Broomfield | 35 min |
| May 2, 3:42 AM MDT | Winter Storm Warning | BOU | Boulder, Clear Creek, Gilpin, Grand, Jackson, Jefferson and 3 more | 34 hr |
| May 2, 10:36 AM MDT | Special Weather Statement | BOU | Boulder | 24 min |
| May 2, 11:01 AM MDT | Special Weather Statement | BOU | Broomfield | 29 min |
| May 2, 11:40 AM MDT | Severe Thunderstorm Warning | BOU | Adams, Arapahoe, Denver | 50 min |
| May 2, 1:17 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Logan, Morgan, Washington | 28 min |
| May 2, 2:13 PM MDT | Severe Thunderstorm Warning | BOU | Lincoln | 32 min |
| May 2, 2:19 PM MDT | Winter Weather Advisory | BOU | Boulder, Clear Creek, Douglas, Gilpin, Grand, Jackson and 3 more | 23 hr |
| May 2, 5:04 PM MDT | Special Weather Statement | BOU | Weld | 41 min |
| May 2, 5:47 PM MDT | Areal Flood Advisory | BOU | Boulder | 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.