Alert archive / Colorado / Flash Flood Warnings in 2021
Flash Flood Warning 21, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this flash flood warning at Jul 5, 2021, 2:00 PM MDT for Grand County, Colorado. It was in force for 90 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 5, 2021, 2:00 PM MDT (20:00 UTC)
- Expired
- Jul 5, 2021, 3:30 PM MDT
- In force
- 90 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
- Flood severity
- None
County Grand County, CO
The radar
The Denver radar (KFTG), 148 km from the middle of the area, began a volume at 20:01 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, 8.0 hours before the alert went out and 237 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
- 5 J/kg
- Mixed-layer CIN
- -276 J/kg
- Mixed-layer LCL
- 3199 m above ground
- 0-6 km bulk shear
- 10 kt
- 0-1 km storm-relative helicity
- -13 m²/s²
- 0-3 km storm-relative helicity
- 26 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
185
WGUS55 KBOU 052000
FFWBOU
COC049-052130-
/O.NEW.KBOU.FF.W.0021.210705T2000Z-210705T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
200 PM MDT Mon Jul 5 2021
The National Weather Service in Denver has issued a
* Flash Flood Warning for...
North Central Grand County in north central Colorado...
* Until 330 PM MDT.
* At 200 PM MDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 0.50 and 0.75 inches 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...
mainly rural areas of North Central Grand County
This includes the following streams and drainages...
Buffalo Creek, East Fork Troublesome Creek, Middle Fork Creek,
Ethel Creek, Trail Creek and Willow 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 northwest portion of the East Troublesome burn
area. Rock slides or debris flows can also be expected across rural
roads.
&&
LAT...LON 4031 10621 4031 10608 4023 10609 4024 10622
FLASH FLOOD...RADAR INDICATED
$$
RPK1 follow-up statement
219
WGUS75 KBOU 052030
FFSBOU
Flash Flood Statement
National Weather Service Denver CO
230 PM MDT Mon Jul 5 2021
COC049-052130-
/O.CON.KBOU.FF.W.0021.000000T0000Z-210705T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Grand CO-
230 PM MDT Mon Jul 5 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 330 PM MDT THIS
AFTERNOON FOR NORTH CENTRAL GRAND COUNTY...
At 230 PM MDT, Doppler radar indicated thunderstorms producing heavy
rain across the warned area. Between 0.75 and 1 inch of rain has
fallen. Flash flooding is ongoing or expected to begin shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flash flooding of small creeks and streams, gulches,
roads, and poor drainage and low-lying areas.
Some locations that will experience flash flooding include...
mainly rural areas of North Central Grand County
This includes the following streams and drainages...
Buffalo Creek, East Fork Troublesome Creek, Middle Fork Creek,
Ethel Creek, Trail Creek and Willow Creek.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Heavy Rainfall will cause flash flooding of small creeks, streams,
and ditches in the northwest portion East Troublesome burn area.
Rock slides or debris flows can also be expected across rural roads.
&&
LAT...LON 4031 10621 4031 10608 4023 10609 4024 10622
FLASH FLOOD...RADAR INDICATED
$$
RPKThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 5, 3:13 AM MDT | Flash Flood Watch | BOU | Boulder, Grand, Jackson, Larimer, Summit | 21 hr |
| Jul 5, 1:29 PM MDT | Areal Flood Advisory | BOU | Park | 91 min |
| Jul 5, 1:36 PM MDT | Areal Flood Advisory | BOU | Grand | 84 min |
| Jul 5, 1:39 PM MDT | Flash Flood Warning | BOU | Larimer | 96 min |
| Jul 5, 1:53 PM MDT | Areal Flood Advisory | BOU | Larimer | 82 min |
| Jul 5, 2:12 PM MDT | Flash Flood Warning | BOU | Larimer | 93 min |
| Jul 5, 2:22 PM MDT | Special Weather Statement | BOU | Teller | 23 min |
| Jul 5, 2:23 PM MDT | Areal Flood Advisory | BOU | Park | 97 min |
| Jul 5, 2:44 PM MDT | Special Weather Statement | BOU | Clear Creek | 31 min |
| Jul 5, 3:28 PM MDT | Flash Flood Warning | BOU | Grand | 92 min |
| Jul 5, 4:18 PM MDT | Areal Flood Advisory | BOU | Clear Creek, Park | 87 min |
| Jul 5, 5:14 PM MDT | Areal Flood Advisory | BOU | Arapahoe, Douglas | 91 min |
| Jul 5, 5:31 PM MDT | Flash Flood Warning | BOU | Grand | 89 min |
| Jul 5, 5:51 PM MDT | Special Weather Statement | BOU | Denver | 24 min |
| Jul 5, 5:53 PM MDT | Areal Flood Advisory | BOU | Arapahoe | 97 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.