Alert archive / Idaho / Flash Flood Warnings in 2021

Flash Flood Warning 4, NWS Pocatello, ID

July 28, 2021Bear Lake County, Franklin County, Idaho

NWS Pocatello, ID issued this flash flood warning at Jul 28, 2021, 10:45 AM MDT for Bear Lake County, Franklin 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: Jul 28, 2021, 10:45 AM MDT (16:45 UTC)
Expired: Jul 28, 2021, 1:45 PM MDT
In force: 3 hr
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), 115 km from the middle of the area, began a volume at 16:45 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, 4.8 hours before the alert went out and 145 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: 104 J/kg
Mixed-layer CIN: -191 J/kg
Mixed-layer LCL: 2082 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 67 m²/s²
0-3 km storm-relative helicity: 48 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

298 
WGUS55 KPIH 281645
FFWPIH
IDC007-041-281945-
/O.NEW.KPIH.FF.W.0004.210728T1645Z-210728T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Pocatello ID
1045 AM MDT Wed Jul 28 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 145 PM MDT.

* At 1045 AM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 1 inch of rain 
  has fallen. 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...
  Western Bear Lake Idaho Portion 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 4200 11168 4210 11166 4212 11155 4211 11142
      4200 11139

FLASH FLOOD...RADAR INDICATED

$$

KB

1 follow-up statement

424 
WGUS75 KPIH 281810
FFSPIH

Flash Flood Statement
National Weather Service Pocatello ID
1210 PM MDT Wed Jul 28 2021

IDC007-041-281945-
/O.CON.KPIH.FF.W.0004.000000T0000Z-210728T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bear Lake ID-Franklin ID-
1210 PM MDT Wed Jul 28 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 145 PM MDT THIS 
AFTERNOON FOR SOUTHWESTERN BEAR LAKE AND SOUTHEASTERN FRANKLIN 
COUNTIES...

At 1210 PM MDT, Doppler radar indicated earlier thunderstorms 
produced heavy rain across the warned area. Around 1 inch of rain 
has fallen. 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...
  Western Bear Lake Idaho Portion 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 4200 11168 4210 11166 4212 11155 4211 11142
      4200 11139

FLASH FLOOD...RADAR INDICATED

$$

KB

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 27, 11:19 PM MDT	Special Weather Statement	PIH	Minidoka	56 min
Jul 28, 10:18 AM MDT	Special Weather Statement	PIH	Bear Lake	42 min
Jul 28, 10:48 AM MDT	Special Weather Statement	PIH	Bingham	42 min
Jul 28, 11:14 AM MDT	Special Weather Statement	PIH	Fremont	46 min
Jul 28, 11:34 AM MDT	Special Weather Statement	PIH	Bear Lake	41 min
Jul 28, 11:57 AM MDT	Special Weather Statement	PIH	Custer	63 min
Jul 28, 12:42 PM MDT	Special Weather Statement	PIH	Bonneville	48 min
Jul 28, 2:20 PM MDT	Flash Flood Warning	PIH	Blaine, Custer	2 hr
Jul 28, 4:09 PM MDT	Special Weather Statement	PIH	Bear Lake	51 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.