Alert archive / Idaho / Flash Flood Warnings in 2021
Flash Flood Warning 2, NWS Missoula, MT
NWS Missoula, MT issued this flash flood warning at Aug 1, 2021, 6:30 PM MDT for Lemhi County, Idaho. It was in force for 3 hr. 2 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Aug 1, 2021, 6:30 PM MDT (00:30 UTC)
- Expired
- Aug 1, 2021, 9:30 PM MDT
- In force
- 3 hr
- Issued by
- NWS Missoula, MT
- Area
- Storm-based polygon
- Flood severity
- None
County Lemhi County, ID
The radar
The Pocatello radar (KSFX), 224 km from the middle of the area, began a volume at 00:31 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 1, 6:56 PM MDT | FLASH FLOOD | 8 Nne Ellis, ID | IDAHO DEPARTMENT OF TRANSPORTATION REPORTS ROCK FALL HAS BLOCKED US 93 FROM PAHSIMEROI ROAD TO MCKIM CREEK ROAD ASSOCIATED WITH HEAVY RAINFALL. INCIDENT WAS CLEARED AT 844 PM. |
| Aug 1, 8:30 PM MDT | FLASH FLOOD | 8 S Williams Lake, ID | IDAHO OF TRANSPORTATION REPORTS NUMEROUS ROCK AND MUDSLIDES ON US 93 FROM MILEPOSTS 281-285 IN THE ELK BEND AREA. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Boise Airport, ID (KBOI), launched 00:00Z, 0.5 hours before the alert went out and 228 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
- 97 J/kg
- Mixed-layer CIN
- -89 J/kg
- Mixed-layer LCL
- 1640 m above ground
- 0-6 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- -6 m²/s²
- 0-3 km storm-relative helicity
- 11 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
261
WGUS55 KMSO 020030
FFWMSO
IDC059-020330-
/O.NEW.KMSO.FF.W.0002.210802T0030Z-210802T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Missoula MT
630 PM MDT Sun Aug 1 2021
The National Weather Service in Missoula has issued a
* Flash Flood Warning for...
Central Lemhi County in east central Idaho...
This includes the following Specific Areas...
Highway 93 8 miles south of Salmon to Ellis and Highway 93 north of
Ellis.
* Until 930 PM MDT.
* At 630 PM MDT, Doppler radar indicated thunderstorms producing
heavy rain across 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.
* Highway 93 8 miles south of Salmon to Ellis.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 4476 11410 4478 11410 4487 11408 4490 11403
4496 11399 4502 11399 4509 11396 4511 11390
4510 11391 4507 11386 4498 11387 4468 11396
4469 11405 4470 11405 4471 11405 4476 11408
FLASH FLOOD...RADAR INDICATED
$$1 follow-up statement
680
WGUS75 KMSO 020322
FFSMSO
Flash Flood Statement
National Weather Service Missoula MT
922 PM MDT Sun Aug 1 2021
IDC059-020332-
/O.EXP.KMSO.FF.W.0002.000000T0000Z-210802T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lemhi ID-
922 PM MDT Sun Aug 1 2021
...FLASH FLOOD WARNING WILL EXPIRE AT 930 PM MDT THIS EVENING FOR
CENTRAL LEMHI COUNTY...
The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.
LAT...LON 4476 11410 4478 11410 4487 11408 4490 11403
4496 11399 4502 11399 4509 11396 4511 11390
4510 11391 4507 11386 4498 11387 4468 11396
4469 11405 4470 11405 4471 11405 4476 11408
$$The office that day
Everything else NWS Missoula, MT issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 1, 7:22 PM MDT | Areal Flood Advisory | MSO | Idaho | 113 min |
| Aug 1, 7:53 PM MDT | Areal Flood Advisory | MSO | Idaho | 112 min |
| Aug 1, 7:59 PM MDT | Areal Flood Warning | MSO | Lemhi | 3 hr |
| Aug 1, 8:15 PM MDT | Areal Flood Advisory | MSO | Idaho | 2 hr |
| Aug 1, 10:01 PM MDT | Areal Flood Advisory | MSO | Idaho | 119 min |
| Aug 2, 10:09 AM MDT | Flash Flood Watch | MSO | Lemhi | 9 hr |
| Aug 2, 5:59 PM MDT | Dense Fog Advisory | MSO | Idaho | 17 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.