Alert archive / Idaho / Flash Flood Warnings in 2021

Flash Flood Warning 3, NWS Pocatello, ID

July 27, 2021Bear Lake County, Franklin County, Idaho

NWS Pocatello, ID issued this flash flood warning at Jul 27, 2021, 4:32 PM MDT for Bear Lake County, Franklin County, Idaho. It was in force for 115 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 27, 2021, 4:32 PM MDT (22:32 UTC)
Expired
Jul 27, 2021, 6:27 PM MDT
In force
115 min
Issued by
NWS Pocatello, ID
Area
Storm-based polygon
Flood severity
None

Counties Bear Lake County, ID, Franklin County, ID

The radar

The Salt Lake City radar (KMTX), 118 km from the middle of the area, began a volume at 22:36 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

Salt Lake City I, UT (KSLC), launched 12:00Z, 10.5 hours before the alert went out and 146 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.

Skew-T log-pSkew-T log-p diagram, Salt Lake City I, UT at 12:00Z on 2021-07-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 80 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Salt Lake City I, UT at 12:00Z on 2021-07-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -23 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
80 J/kg
Mixed-layer CIN
-313 J/kg
Mixed-layer LCL
1998 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
-23 m²/s²
0-3 km storm-relative helicity
37 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

271 
WGUS55 KPIH 272232
FFWPIH
IDC007-041-280145-
/O.NEW.KPIH.FF.W.0003.210727T2232Z-210728T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Pocatello ID
432 PM MDT Tue Jul 27 2021

The National Weather Service in Pocatello has issued a

* Flash Flood Warning for...
  Southwestern Bear Lake County in southeastern Idaho...
  Southeastern Franklin County in southeastern Idaho...

* Until 745 PM MDT.

* At 432 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.

* Some locations that will experience flash flooding include...
  Saint Charles and Minnetonka Cave.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Flooding is occurring or is imminent. It is important to know where 
you are relative to streams, rivers, or creeks which can become 
killers in heavy rains. Campers and hikers should avoid streams or 
creeks.

&&

LAT...LON 4213 11158 4213 11139 4200 11141 4200 11157
      4200 11160

FLASH FLOOD...RADAR INDICATED

$$

DH
1 follow-up statement
898 
WGUS75 KPIH 280027
FFSPIH

Flash Flood Statement
National Weather Service Pocatello ID
627 PM MDT Tue Jul 27 2021

IDC007-041-280037-
/O.CAN.KPIH.FF.W.0003.000000T0000Z-210728T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bear Lake ID-Franklin ID-
627 PM MDT Tue Jul 27 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHWESTERN BEAR LAKE AND 
SOUTHEASTERN FRANKLIN COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 4213 11158 4213 11139 4200 11141 4200 11157
      4200 11160

$$

DH

The office that day

Everything else NWS Pocatello, ID issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 27, 2:05 AM MDTRed Flag WarningPIHCuster, Idaho, Lemhi, Valley20 hr
Jul 27, 3:05 PM MDTFlash Flood WarningPIHCassia3 hr
Jul 27, 3:31 PM MDTSpecial Weather StatementPIHBear Lake44 min
Jul 27, 4:12 PM MDTSpecial Weather StatementPIHBear Lake48 min

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.