Alert archive / Idaho / Flash Flood Warnings in 2021

Flash Flood Warning 21, NWS Pocatello, ID

August 4, 2021Cassia County, Idaho

NWS Pocatello, ID issued this flash flood warning at Aug 4, 2021, 7:36 PM MDT for Cassia County, Idaho. It was in force for 114 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: Aug 4, 2021, 7:36 PM MDT (01:36 UTC)
Expired: Aug 4, 2021, 9:30 PM MDT
In force: 114 min
Issued by: NWS Pocatello, ID
Area: Storm-based polygon
Flood severity: None

County Cassia County, ID

The radar

The Pocatello radar (KSFX), 151 km from the middle of the area, began a volume at 01:36 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

Elko, NV (KLKN), launched 00:00Z, 1.6 hours before the alert went out and 151 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 426 J/kg
Mixed-layer CIN: -62 J/kg
Mixed-layer LCL: 3372 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 44 m²/s²
0-3 km storm-relative helicity: 68 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

411 
WGUS55 KPIH 050136
FFWPIH
IDC031-050330-
/O.NEW.KPIH.FF.W.0021.210805T0136Z-210805T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Pocatello ID
736 PM MDT Wed Aug 4 2021

The National Weather Service in Pocatello has issued a

* Flash Flood Warning for...
  The Badger Fire Burn Area in...
  Southwestern Cassia County in southeastern Idaho...

* Until 930 PM MDT.

* At 736 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain over the Badger Fire Burn Area. Between 0.25 and 0.5 
  inches of rain have fallen. Flash flooding is ongoing or expected 
  to begin shortly.

Excessive rainfall over the burn scar will result in debris flow 
moving through the Big Cottonwood Creek, South Cottonwood Creek and 
Trapper Creek. The debris flow can consist of rock, mud, vegetation 
and other loose materials.

  HAZARD...Flash flooding caused by thunderstorms in and around
           the Badger Fire Burn Area.

  SOURCE...Radar.

  IMPACT...Flooding of areas in and around the Badger Fire Burn
           Area.

* Some locations that will experience flash flooding include...
  Oakley Reservoir and Bostetter Ranger Station.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a life threatening situation.  Heavy rainfall may cause 
extensive and severe flash flooding of creeks and streams in the 
Badger Fire Burn Area.  Some drainage basins impacted include Big 
Cottonwood Creek and Trapper Creek.  Severe debris flows can also be 
anticipated across roads.  Roads and driveways may be washed away in 
places.  If you encounter flood waters...climb to safety.

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

&&

LAT...LON 4242 11429 4242 11416 4229 11413 4226 11408
      4228 11405 4227 11402 4222 11405 4218 11400
      4220 11395 4219 11392 4217 11394 4212 11403
      4206 11408 4204 11412 4204 11428

FLASH FLOOD...RADAR INDICATED

$$

JK

1 follow-up statement

237 
WGUS75 KPIH 050325
FFSPIH

Flash Flood Statement
National Weather Service Pocatello ID
925 PM MDT Wed Aug 4 2021

IDC031-050335-
/O.EXP.KPIH.FF.W.0021.000000T0000Z-210805T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cassia ID-
925 PM MDT Wed Aug 4 2021

...FLASH FLOOD WARNING FOR THE BADGER FIRE BURN AREA WILL EXPIRE AT 
930 PM MDT THIS EVENING FOR SOUTHWESTERN CASSIA COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Expect periodic lighter rain for the next few hours.

LAT...LON 4242 11429 4242 11416 4229 11413 4226 11408
      4228 11405 4227 11402 4222 11405 4218 11400
      4220 11395 4219 11392 4217 11394 4212 11403
      4206 11408 4204 11412 4204 11428

$$

JKeyes

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 5, 2:01 PM MDT	Special Weather Statement	PIH	Cassia, Minidoka	44 min
Aug 5, 4:29 PM MDT	Special Weather Statement	PIH	Custer	46 min
Aug 5, 5:03 PM MDT	Special Weather Statement	PIH	Minidoka	42 min
Aug 5, 5:04 PM MDT	Special Weather Statement	PIH	Clark	41 min
Aug 5, 5:21 PM MDT	Special Weather Statement	PIH	Custer	39 min
Aug 5, 5:28 PM MDT	Special Weather Statement	PIH	Power	32 min
Aug 5, 5:38 PM MDT	Special Weather Statement	PIH	Minidoka	37 min
Aug 5, 5:57 PM MDT	Special Weather Statement	PIH	Clark	48 min

Nearby

Flash Flood Warnings in Idaho, 2021 Every 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.