Alert archive / Idaho / Flash Flood Warnings in 2017

Flash Flood Warning 2, NWS Pocatello, ID

August 23, 2017Bannock County, Power County, Idaho

NWS Pocatello, ID issued this flash flood warning at Aug 23, 2017, 2:34 PM MDT for Bannock County, Power 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
Aug 23, 2017, 2:34 PM MDT (20:34 UTC)
Expired
Aug 23, 2017, 5:30 PM MDT
In force
3 hr
Issued by
NWS Pocatello, ID
Area
Storm-based polygon
Flood severity
None

Counties Bannock County, ID, Power County, ID

The radar

The Pocatello radar (KSFX), 43 km from the middle of the area, began a volume at 20:35 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, 8.6 hours before the alert went out and 224 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 2017-08-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 114 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 2017-08-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -29 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
114 J/kg
Mixed-layer CIN
-227 J/kg
Mixed-layer LCL
2053 m above ground
0-6 km bulk shear
4 kt
0-1 km storm-relative helicity
-29 m²/s²
0-3 km storm-relative helicity
2 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

711 
WGUS55 KPIH 232034
FFWPIH
IDC005-077-232330-
/O.NEW.KPIH.FF.W.0002.170823T2034Z-170823T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Pocatello ID
234 PM MDT WED AUG 23 2017

The National Weather Service in Pocatello has issued a

* Flash Flood Warning for...
  Central Bannock County in southeastern Idaho...
  East central Power County in southeastern Idaho...

* Until 530 PM MDT

* At 230 PM MDT, Doppler radar indicated heavy rain approaching the 
  Powerline Fire burn scar area. Doppler Radar indicates the 
  potential for two inch per hour or greater rainfall rates. Flash 
  flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Fort Hall Bannock Creek Lodge and the Rattlesnake Creek Drainage 
  Region within the Powerline Burn Scar area.

Excessive rainfall over the burn scar will result in debris flow 
moving through the Rattlesnake Creek Drainage near Rattlesnake Road. 
The debris flow can consist of rock, mud, ash, vegetation and other 
loose materials.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Stay away or be swept away. River banks and culverts can become
unstable and unsafe.

Move away from recently burned areas. Life-threatening flooding of
creeks, roads and normally dry arroyos is likely. The heavy rains
will likely trigger rockslides, mudslides and debris flows in steep
terrain, especially in and around these areas.

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 4285 11246 4256 11248 4257 11260 4283 11284

$$

AD/DMH
1 follow-up statement
737 
WGUS75 KPIH 232223
FFSPIH

Flash Flood Statement
National Weather Service Pocatello ID
423 PM MDT WED AUG 23 2017

IDC005-077-232231-
/O.CAN.KPIH.FF.W.0002.000000T0000Z-170823T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bannock ID-Power ID-
423 PM MDT WED AUG 23 2017

...THE FLASH FLOOD WARNING FOR CENTRAL BANNOCK AND EAST CENTRAL POWER
COUNTIES IS CANCELLED...

The heavy rain has ended. Flooding is no longer expected to pose an 
immediate threat. Doppler Radar indicates up to one and a half 
inches of rain may have fell over for southeast portions of the burn 
area.

LAT...LON 4285 11246 4256 11248 4257 11260 4283 11284

$$

AD/VALLE

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 23, 1:05 PM MDTSpecial Weather StatementPIHOneida55 min
Aug 23, 1:55 PM MDTSpecial Weather StatementPIHPower50 min
Aug 23, 2:43 PM MDTSpecial Weather StatementPIHOneida47 min
Aug 23, 2:52 PM MDTSpecial Weather StatementPIHOneida38 min
Aug 23, 3:16 PM MDTSpecial Weather StatementPIHBannock44 min
Aug 23, 3:50 PM MDTSpecial Weather StatementPIHCassia40 min
Aug 23, 4:07 PM MDTSevere Thunderstorm WarningPIHCassia38 min

Nearby

Flash Flood Warnings in Idaho, 2017Every flash flood warning in 2017

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.