Flash Flood Warning 3, NWS Boise, ID

Issued

Jul 31, 2021, 7:39 PM MDT (01:39 UTC)

Expired

Jul 31, 2021, 10:45 PM MDT

In force

3 hr

Issued by

NWS Boise, ID

Area

Storm-based polygon

Flood severity

None

County Twin Falls County, ID

The Pocatello radar (KSFX), 163 km from the middle of the area, began a volume at 01:41 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.

345 
WGUS55 KBOI 010139
FFWBOI
IDC083-010445-
/O.NEW.KBOI.FF.W.0003.210801T0139Z-210801T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Boise has issued a

* Flash Flood Warning for...
  South Central Twin Falls County in south central Idaho...

* Until 1045 PM MDT.

* At 739 PM MDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area, including the Badger Fire Burn 
  Area. Between 0.5 and 1 inch of rain has fallen. The expected 
  rainfall rate is 0.25 to 0.75 inches 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, poor
           drainage and low-lying areas. Debris flows may move
           through the Rock Creek drainage due to the Badger Fire
           Burn Area.

* Some locations that will experience flash flooding include...Rock 
  Creek, McMullen Creek, Cottonwood Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

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

&&

LAT...LON 4244 11429 4240 11429 4237 11429 4235 11429
      4233 11429 4233 11428 4213 11428 4212 11428
      4210 11428 4203 11428 4203 11449 4244 11451

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...0.25-0.75 INCHES IN 1 HOUR

$$

BOI

223 
WGUS75 KBOI 010355
FFSBOI

Flash Flood Statement
National Weather Service Boise ID
955 PM MDT Sat Jul 31 2021

IDC083-010445-
/O.CON.KBOI.FF.W.0003.000000T0000Z-210801T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Twin Falls ID-
955 PM MDT Sat Jul 31 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1045 PM MDT THIS 
EVENING FOR EASTERN TWIN FALLS COUNTY...

At 955 PM MDT, Doppler radar indicated that the thunderstorms which 
produced heavy rain over the Badger Fire Burn Area and eastern Twin 
Falls County have moved out of the area. However, excessive runoff 
from earlier heavy rain and debris flows remain possible in lower 
reaches of the Rock Creek drainage.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, county
         roads, as well as  poor drainage and low-lying areas.

This includes the following streams and drainages...
  Rock Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

Move away from recently burned areas. Runoff from earlier heavy 
rains will likely trigger rockslides, mudslides and debris flows in 
steep terrain.

&&

LAT...LON 4244 11429 4233 11429 4233 11428 4230 11428
      4227 11428 4225 11428 4222 11428 4222 11431
      4223 11433 4223 11435 4225 11436 4243 11437

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...0.25 INCHES IN 1 HOUR

$$

BOI

885 
WGUS75 KBOI 010442
FFSBOI

Flash Flood Statement
National Weather Service Boise ID
1042 PM MDT Sat Jul 31 2021

IDC083-010452-
/O.EXP.KBOI.FF.W.0003.000000T0000Z-210801T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Twin Falls ID-
1042 PM MDT Sat Jul 31 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 1045 PM MDT THIS EVENING FOR 
EASTERN TWIN FALLS COUNTY...

Flooding is no longer expected to pose a threat. 

A Flash Flood Watch remains in effect until 600 PM MDT Monday for 
portions of Idaho and Oregon.

LAT...LON 4244 11429 4233 11429 4233 11428 4230 11428
      4227 11428 4225 11428 4222 11428 4222 11431
      4223 11433 4223 11435 4225 11436 4243 11437

$$

BOI

Flash Flood Warnings in Idaho, 2021Every flash flood warning in 2021

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.