Alert archive / Idaho / Flash Flood Warnings in 2021
Flash Flood Warning 9, NWS Boise, ID
NWS Boise, ID issued this flash flood warning at Aug 1, 2021, 5:32 PM MDT for Elmore 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, 5:32 PM MDT (23:32 UTC)
- Expired
- Aug 1, 2021, 8:30 PM MDT
- In force
- 3 hr
- Issued by
- NWS Boise, ID
- Area
- Storm-based polygon
- Flood severity
- None
County Elmore County, ID
The radar
The Boise radar (KCBX), 50 km from the middle of the area, began a volume at 23:33 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, 11.5 hours before the alert went out and 53 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.
810
WGUS55 KBOI 012332
FFWBOI
IDC039-020230-
/O.NEW.KBOI.FF.W.0009.210801T2332Z-210802T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Boise ID
532 PM MDT Sun Aug 1 2021
The National Weather Service in Boise has issued a
* Flash Flood Warning for...
Central Elmore County in southwestern Idaho...
* Until 830 PM MDT.
* At 532 PM MDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 1 and 2 inches of rain
have fallen. Additional rainfall amounts of 0.5 to 1 inch 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...
Mountain Home.
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 4319 11581 4327 11584 4342 11573 4336 11560
4325 11560 4317 11564 4312 11571
FLASH FLOOD...RADAR INDICATED
$$
ST2 follow-up statements
251
WGUS75 KBOI 020136
FFSBOI
Flash Flood Statement
National Weather Service Boise ID
736 PM MDT Sun Aug 1 2021
IDC039-020230-
/O.CON.KBOI.FF.W.0009.000000T0000Z-210802T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Elmore ID-
736 PM MDT Sun Aug 1 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 830 PM MDT THIS
EVENING FOR CENTRAL ELMORE COUNTY...
At 736 PM MDT, Doppler radar indicated thunderstorms produced heavy
rain across the warned area. Between 1 and 2 inches of rain have
fallen. Flash flooding is ongoing.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flash flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other poor
drainage and low-lying areas.
Some locations that will experience flash flooding include...
Mountain Home.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Remain alert for flooding even in locations not receiving rain. Dry
washes, streams, and rivers can become raging killer currents in a
matter of minutes, even from distant rainfall.
Please report observed flooding to local emergency services or law
enforcement and request they pass this information to the National
Weather Service when you can do so safely.
&&
LAT...LON 4319 11581 4327 11584 4342 11573 4336 11560
4325 11560 4317 11564 4312 11571
FLASH FLOOD...RADAR INDICATED
$$
ST397
WGUS75 KBOI 020223
FFSBOI
Flash Flood Statement
National Weather Service Boise ID
823 PM MDT Sun Aug 1 2021
IDC039-020233-
/O.EXP.KBOI.FF.W.0009.000000T0000Z-210802T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Elmore ID-
823 PM MDT Sun Aug 1 2021
...FLASH FLOOD WARNING WILL EXPIRE AT 830 PM MDT THIS EVENING FOR
CENTRAL ELMORE 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 4319 11581 4327 11584 4342 11573 4336 11560
4325 11560 4317 11564 4312 11571
$$
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, 4:01 PM MDT | Flash Flood Warning | BOI | Owyhee | 3 hr |
| Aug 1, 4:49 PM MDT | Areal Flood Advisory | 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.