Alert archive / Idaho / Flash Flood Warnings in 2021
Flash Flood Warning 8, NWS Boise, ID
NWS Boise, ID issued this flash flood warning at Aug 1, 2021, 4:01 PM MDT for Owyhee County, Idaho. 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
- Aug 1, 2021, 4:01 PM MDT (22:01 UTC)
- Expired
- Aug 1, 2021, 7:00 PM MDT
- In force
- 3 hr
- Issued by
- NWS Boise, ID
- Area
- Storm-based polygon
- Flood severity
- None
County Owyhee County, ID
The radar
The Boise radar (KCBX), 87 km from the middle of the area, began a volume at 22:01 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
Boise Airport, ID (KBOI), launched 12:00Z, 10.0 hours before the alert went out and 96 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
- 4 J/kg
- Mixed-layer CIN
- -186 J/kg
- Mixed-layer LCL
- 1142 m above ground
- 0-6 km bulk shear
- 16 kt
- 0-1 km storm-relative helicity
- 78 m²/s²
- 0-3 km storm-relative helicity
- 92 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
908
WGUS55 KBOI 012201
FFWBOI
IDC073-020100-
/O.NEW.KBOI.FF.W.0008.210801T2201Z-210802T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Boise ID
401 PM MDT Sun Aug 1 2021
The National Weather Service in Boise has issued a
* Flash Flood Warning for...
Central Owyhee County in southwestern Idaho...
* Until 700 PM MDT.
* At 401 PM MDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 0.5 and 1 inch of rain
has fallen. Additional rainfall amounts of 0.5 to 1.5 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, urban
areas, highways, streets and underpasses as well as
other poor drainage and low-lying areas.
* Some locations that will experience flash flooding include...
Big Horse Basin Gap and Chalk Hills.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Remain alert for flooding even in locations not receiving rain. Dry
washes, streams, and rivers can become raging killer currents in a
matter of minutes, even from distant rainfall.
Please report observed flooding to local emergency services or law
enforcement and request they pass this information to the National
Weather Service when you can do so safely.
&&
LAT...LON 4260 11618 4275 11614 4288 11588 4286 11585
4280 11590 4271 11593 4259 11593
FLASH FLOOD...RADAR INDICATED
$$
ST1 follow-up statement
243
WGUS75 KBOI 020052
FFSBOI
Flash Flood Statement
National Weather Service Boise ID
652 PM MDT Sun Aug 1 2021
IDC073-020102-
/O.EXP.KBOI.FF.W.0008.000000T0000Z-210802T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Owyhee ID-
652 PM MDT Sun Aug 1 2021
...FLASH FLOOD WARNING WILL EXPIRE AT 7 PM MDT THIS EVENING FOR
CENTRAL OWYHEE COUNTY...
The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.
A Flash Flood Watch remains in effect until 1200 AM MDT for portions
of south central Idaho, southwest Idaho and west central Idaho.
LAT...LON 4260 11618 4275 11614 4288 11588 4286 11585
4280 11590 4271 11593 4259 11593
$$
STThe office that day
Everything else NWS Boise, ID issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 31, 6:40 PM MDT | Special Weather Statement | BOI | Twin Falls | 35 min |
| Jul 31, 7:06 PM MDT | Flash Flood Warning | BOI | Owyhee, Twin Falls | 3 hr |
| Jul 31, 7:39 PM MDT | Flash Flood Warning | BOI | Twin Falls | 3 hr |
| Jul 31, 9:32 PM MDT | Special Weather Statement | BOI | Ada | 28 min |
| Jul 31, 9:33 PM MDT | Areal Flood Advisory | BOI | Elmore, Owyhee | 117 min |
| Jul 31, 10:12 PM MDT | Flash Flood Warning | BOI | Ada, Boise | 3 hr |
| Jul 31, 11:58 PM MDT | Flash Flood Warning | BOI | Canyon, Gem, Owyhee, Payette | 2 hr |
| Aug 1, 12:43 AM MDT | Areal Flood Advisory | BOI | Payette, Washington | 2 hr |
| Aug 1, 1:47 AM MDT | Areal Flood Advisory | BOI | Camas | 103 min |
| Aug 1, 1:11 PM MDT | Special Weather Statement | BOI | Twin Falls | 49 min |
| Aug 1, 1:25 PM MDT | Areal Flood Advisory | BOI | Twin Falls | 3 hr |
| Aug 1, 2:15 PM MDT | Special Weather Statement | BOI | Jerome | 60 min |
| Aug 1, 2:39 PM MDT | Flash Flood Warning | BOI | Elmore | 5 hr |
| Aug 1, 3:21 PM MDT | Areal Flood Advisory | BOI | Jerome, Twin Falls | 3 hr |
| Aug 1, 3:39 PM MDT | Flash Flood Warning | BOI | Camas, Elmore | 3 hr |
| Aug 1, 4:49 PM MDT | Areal Flood Advisory | BOI | Elmore | 3 hr |
| Aug 1, 5:32 PM MDT | Flash Flood Warning | BOI | Elmore | 3 hr |
| Aug 1, 5:39 PM MDT | Areal Flood Advisory | BOI | Owyhee | 2 hr |
Nearby
Flash Flood Warnings in Idaho, 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.