Alert archive / Idaho / Flash Flood Warnings in 2021

Flash Flood Warning 14, NWS Pocatello, ID

July 31, 2021Power County, Idaho

NWS Pocatello, ID issued this flash flood warning at Jul 31, 2021, 3:50 PM MDT for Power County, Idaho. It was in force for 77 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 31, 2021, 3:50 PM MDT (21:50 UTC)
Expired: Jul 31, 2021, 5:07 PM MDT
In force: 77 min
Issued by: NWS Pocatello, ID
Area: Storm-based polygon
Flood severity: None

County Power County, ID

The radar

The Pocatello radar (KSFX), 66 km from the middle of the area, began a volume at 21:50 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, 9.8 hours before the alert went out and 204 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: 149 J/kg
Mixed-layer CIN: -128 J/kg
Mixed-layer LCL: 1716 m above ground
0-6 km bulk shear: 5 kt
0-1 km storm-relative helicity: 44 m²/s²
0-3 km storm-relative helicity: 76 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

225 
WGUS55 KPIH 312150
FFWPIH
IDC077-010000-
/O.NEW.KPIH.FF.W.0014.210731T2150Z-210801T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Pocatello ID
350 PM MDT Sat Jul 31 2021

The National Weather Service in Pocatello has issued a

* Flash Flood Warning for...
  Southeastern Power County in southeastern Idaho...

* Until 600 PM MDT.

* At 350 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2.5 inches of 
  rain have fallen. The expected rainfall rate is 0.5 to 1 inch in 1 
  hour. 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...
  mainly rural areas of Southeastern Power County...including the 
  west side of the Arbon Valley and the east side of the Rockland 
  Valley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4260 11277 4260 11260 4242 11259 4242 11276
      4246 11277

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...0.5-1 INCH IN 1 HOUR

$$

JK

1 follow-up statement

976 
WGUS75 KPIH 312307
FFSPIH

Flash Flood Statement
National Weather Service Pocatello ID
507 PM MDT Sat Jul 31 2021

IDC077-312317-
/O.CAN.KPIH.FF.W.0014.000000T0000Z-210801T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Power ID-
507 PM MDT Sat Jul 31 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHEASTERN POWER COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat.

A Flash Flood Watch remains in effect until 900 PM MDT Monday for 
portions of eastern Idaho and southeast Idaho.

LAT...LON 4260 11277 4260 11260 4242 11259 4242 11276
      4246 11277

$$

JK

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 31, 8:46 AM MDT	Areal Flood Advisory	PIH	Bingham, Bonneville, Jefferson	119 min
Jul 31, 12:20 PM MDT	Special Weather Statement	PIH	Power	40 min
Jul 31, 1:08 PM MDT	Areal Flood Advisory	PIH	Power	29 min
Jul 31, 1:08 PM MDT	Areal Flood Advisory	PIH	Bannock	112 min
Jul 31, 1:37 PM MDT	Flash Flood Warning	PIH	Power	2 hr
Jul 31, 1:46 PM MDT	Areal Flood Advisory	PIH	Bannock, Power	119 min
Jul 31, 1:55 PM MDT	Areal Flood Advisory	PIH	Bear Lake	2 hr
Jul 31, 2:04 PM MDT	Areal Flood Advisory	PIH	Caribou	3 hr
Jul 31, 2:16 PM MDT	Areal Flood Advisory	PIH	Bear Lake, Franklin	3 hr
Jul 31, 2:28 PM MDT	Areal Flood Advisory	PIH	Bannock, Oneida, Power	3 hr
Jul 31, 2:38 PM MDT	Special Weather Statement	PIH	Bear Lake	37 min
Jul 31, 3:01 PM MDT	Areal Flood Advisory	PIH	Caribou	6 min
Jul 31, 3:07 PM MDT	Flash Flood Warning	PIH	Caribou	113 min
Jul 31, 3:10 PM MDT	Areal Flood Advisory	PIH	Bingham	3 hr
Jul 31, 3:20 PM MDT	Special Weather Statement	PIH	Bonneville	25 min
Jul 31, 3:32 PM MDT	Areal Flood Advisory	PIH	Bannock	3 hr
Jul 31, 4:02 PM MDT	Areal Flood Advisory	PIH	Cassia	118 min
Jul 31, 4:06 PM MDT	Areal Flood Advisory	PIH	Bannock, Franklin, Oneida	3 hr
Jul 31, 4:42 PM MDT	Flash Flood Warning	PIH	Bannock, Franklin, Oneida	2 hr
Jul 31, 5:14 PM MDT	Areal Flood Advisory	PIH	Franklin	2 hr
Jul 31, 5:45 PM MDT	Areal Flood Advisory	PIH	Cassia	64 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.