Alert archive / Idaho / Flash Flood Warnings in 2026

Flash Flood Warning 3, NWS Pocatello, ID

July 17, 2026Custer County, Idaho

NWS Pocatello, ID issued this flash flood warning at Jul 17, 2026, 5:11 PM MDT for Custer County, Idaho. It was in force for 4 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 17, 2026, 5:11 PM MDT (23:11 UTC)
Expired: Jul 17, 2026, 9:15 PM MDT
In force: 4 hr
Issued by: NWS Pocatello, ID
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Custer County, ID

The radar

The Boise radar (KCBX), 124 km from the middle of the area, began a volume at 23:11 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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this flash flood warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The text

As transmitted.

399 
WGUS55 KPIH 172311
FFWPIH
IDC037-180215-
/O.NEW.KPIH.FF.W.0003.260717T2311Z-260718T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Pocatello ID
511 PM MDT Fri Jul 17 2026

The National Weather Service in Pocatello has issued a

* Flash Flood Warning for...
  The Wapiti burn scar in...
  West Central Custer County in central Idaho...

* Until 815 PM MDT.

* At 511 PM MDT, Doppler radar indicated thunderstorms producing
  heavy rain over the Wapiti Burn Scar. 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 Wapiti burn scar. The debris flow
  can consist of rock, mud, vegetation and other loose materials.

  HAZARD...Life threatening flash flooding. Thunderstorms producing
           flash flooding in and around the Wapiti Burn Scar.

  SOURCE...Radar indicated.

  IMPACT...Life threatening flash flooding of areas in and around the
           Wapiti Burn Scar.

* Some locations that will experience flash flooding include...
  Cape Horn Area and Banner Summit.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a life threatening situation. Heavy rainfall will cause
extensive and severe flash flooding of creeks...streams...and ditches
in the Wapiti Burn Scar. 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.

&&

LAT...LON 4417 11511 4419 11512 4421 11517 4422 11516
      4422 11517 4424 11517 4425 11516 4429 11517
      4430 11518 4428 11520 4431 11522 4430 11524
      4432 11526 4440 11518 4435 11509 4440 11504
      4438 11501 4432 11504 4423 11497 4420 11498

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

13

2 follow-up statements

435 
WGUS55 KPIH 180148
FFWPIH
IDC037-180315-
/O.EXT.KPIH.FF.W.0003.000000T0000Z-260718T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Pocatello ID
748 PM MDT Fri Jul 17 2026

The National Weather Service in Pocatello has extended the

* Flash Flood Warning for...
  The Wapiti burn scar in...
  West Central Custer County in central Idaho...

* Until 915 PM MDT.

* At 748 PM MDT, Doppler radar indicated thunderstorms producing
  heavy rain over the Wapiti Burn Scar. Between 0.25 and 0.75 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 Wapiti burn scar. The debris flow
  can consist of rock, mud, vegetation and other loose materials.

  HAZARD...Life threatening flash flooding. Thunderstorms producing
           flash flooding in and around the Wapiti Burn Scar.

  SOURCE...Radar indicated.

  IMPACT...Life threatening flash flooding of areas in and around the
           Wapiti Burn Scar.

* Some locations that will experience flash flooding include...
  Cape Horn Area and Banner Summit.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This is a life threatening situation. Heavy rainfall will cause
extensive and severe flash flooding of creeks...streams...and ditches
in the Wapiti Burn Scar. 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.

&&

LAT...LON 4417 11511 4419 11512 4421 11517 4422 11516
      4422 11517 4424 11517 4425 11516 4429 11517
      4430 11518 4428 11520 4431 11522 4430 11524
      4432 11526 4440 11518 4435 11509 4440 11504
      4438 11501 4432 11504 4423 11497 4420 11498

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

13

232 
WGUS75 KPIH 180311
FFSPIH

Flash Flood Statement
National Weather Service Pocatello ID
911 PM MDT Fri Jul 17 2026

IDC037-180321-
/O.EXP.KPIH.FF.W.0003.000000T0000Z-260718T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Custer ID-
911 PM MDT Fri Jul 17 2026

...FLASH FLOOD WARNING FOR THE WAPITI BURN SCAR WILL EXPIRE AT 915 PM
MDT THIS EVENING FOR WEST CENTRAL CUSTER COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.

&&

LAT...LON 4417 11511 4419 11512 4421 11517 4422 11516
      4422 11517 4424 11517 4425 11516 4429 11517
      4430 11518 4428 11520 4431 11522 4430 11524
      4432 11526 4440 11518 4435 11509 4440 11504
      4438 11501 4432 11504 4423 11497 4420 11498

$$

13

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Pocatello, ID wrote its last area forecast discussion before this flash flood warning went out at Jul 17, 4:19 PM MDT, 52 minutes earlier. Its key messages:

Monsoonal moisture remains in place through next week for more showers and thunderstorms.
Some storms COULD produce decent downpours and gusty winds and hail. With the potential for heavy downpours Friday a flash flood watch is in effect Friday afternoon and evening for the Wapiti Burn Scar near Stanley.
Temperatures SHOULD continue ABOVE AVERAGE but may fluctuate based on early day cloud cover. Sunday and Monday likely the hottest days and also the driest days.

Area forecast discussion, Jul 17, 4:19 PM MDT, 52 minutes before

Area Forecast Discussion
National Weather Service Pocatello ID
419 PM MDT Fri Jul 17 2026

.KEY MESSAGES...

- Monsoonal moisture remains in place through next week for
  more showers and thunderstorms.

- Some storms COULD produce decent downpours and gusty winds and
  hail. With the potential for heavy downpours Friday a flash
  flood watch is in effect Friday afternoon and evening for the
  Wapiti Burn Scar near Stanley.

- Temperatures SHOULD continue ABOVE AVERAGE but may fluctuate
  based on early day cloud cover. Sunday and Monday likely the
  hottest days and also the driest days.

&&

.DISCUSSION...
Issued at 1259 PM MDT Fri Jul 17 2026

Southerly flow aloft continues today into Saturday with showers
and thunderstorms likely this afternoon and evening across
southeast Idaho. Some potential downpours may occur under strong
storms with localized heavy rain and flooding possible. The
Wapiti Burn Scar near Stanley under a flash flood watch.
Saturday will still see at least a slight chance of showers and
thunderstorms. The southerly flow backs off Sunday and the
monsoonal moisture may be temporarily blocked from entering
Idaho and is likely to be the driest and least covered
thunderstorm day in the next week. Low elevation highs likely
in the 90s both Saturday and Sunday with likely more sun than
today. Mountain highs in the 80s. See an increase in southerly
flow again Tuesday with another wetter period Tuesday into the
middle portion of next week. Have at least a chance of showers
and thunderstorms again Tuesday through next Friday. Maybe
slightly cooler high temperatures in expected cloud cover in the
extended time frame with 80s to lower 90s valleys and mid 70s
to mid 80s mountains, but overnight lows very elevated in the
continued humidity and periodic cloud cover.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 418 PM MDT Fri Jul 17 2026

Main concern is scattered thunderstorms this evening. Storms
could reduce visibilities to at least mvfr levels and possibly
lower. Gusts to around 35 kts are certainly possible in and
around storms as well. Most activity should dissipate this
evening.

&&

.FIRE WEATHER...
Issued at 133 PM MDT Fri Jul 17 2026

Monsoonal moisture remains entrenched over central and eastern
Idaho. RED FLAG WARNINGS remain in place across higher
elevations today for scattered thunderstorms. Have started to
see development early this afternoon across the region and
although some will be very wet under the strongest cells not
everyone will see wetting rains with them. Expect most outflow
winds to be in the 30 to 40 mph range due to lack of heating
from cloud cover today but could still see isolated gusts higher
than that. Hail is also likely under the stronger storms.

Showers and storms on Saturday will most likely remain over
higher elevations but even low elevations are at risk for
isolated storms, with any development across 410 and 425
relying on outflow boundaries for a focus. There is a 30-60%
chance tomorrow for gusts over 35 mph and we could still see
some locally heavy rainfall with a few storms. Sunday SUPPOSEDLY
ends up pretty dry with storm chances under 10% and hot
conditions. This seems to be a bit aggressive, in terms of
drying things out, and we may end up actually with at least
isolated storms closer to the Montana and Utah borders.

More southerly flow aloft returns Tuesday after a bit of a break
Sunday and Monday with likely showers and thunderstorms again
Tuesday through next week.

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 9 PM MDT this evening for IDZ411-413-
422-427-475-476.

&&

DISCUSSION...GK
AVIATION...13
FIRE WEATHER...GK

In the hours before

Special weather statement, Jul 17, 12:19 PM MDT, 4 hours 52 minutes before

Special Weather Statement
National Weather Service Pocatello ID
1219 PM MDT Fri Jul 17 2026

IDZ053-062>064-171900-
Big Hole Mountains ID-Upper Snake River Plain ID-Caribou Range ID-
Blackfoot Mountains ID-
1219 PM MDT Fri Jul 17 2026

...STRONG THUNDERSTORMS WILL IMPACT WEST CENTRAL TETON...SOUTHEASTERN
JEFFERSON...NORTH CENTRAL BONNEVILLE AND SOUTHERN MADISON COUNTIES
THROUGH 100 PM MDT...

At 1218 PM MDT, Doppler radar was tracking a cluster of strong
thunderstorms near Ririe Reservoir, moving north at 20 mph.

HAZARD...Wind gusts in excess of 45 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to outdoor objects is
         possible.

Locations impacted include...
Rexburg, Ririe Reservoir, Lorenzo, Iona, Ririe, Archer, Thornton, and
Heise.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 4337 11155 4342 11194 4383 11188 4377 11138
TIME...MOT...LOC 1818Z 192DEG 19KT 4348 11180

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...45 MPH

KB

Special weather statement, Jul 17, 12:46 PM MDT, 4 hours 25 minutes before

Special Weather Statement
National Weather Service Pocatello ID
1246 PM MDT Fri Jul 17 2026

IDZ058-062-171930-
Marsh and Arbon Highlands ID-Blackfoot Mountains ID-
1246 PM MDT Fri Jul 17 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN CARIBOU...
NORTHEASTERN BANNOCK AND SOUTHEASTERN BINGHAM COUNTIES THROUGH 130 PM
MDT...

At 1246 PM MDT, Doppler radar was tracking a strong thunderstorm near
Chesterfield Reservoir, moving north at 20 mph.

HAZARD...Wind gusts in excess of 45 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to outdoor objects is
         possible.

Locations impacted include...
Chesterfield Reservoir, Cutthroat Trout Campground, and Trail Creek
Campground.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 4281 11194 4287 11217 4324 11206 4315 11171
TIME...MOT...LOC 1846Z 199DEG 17KT 4292 11203

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...45 MPH

KB

Special weather statement, Jul 17, 1:07 PM MDT, 4 hours 4 minutes before

Special Weather Statement
National Weather Service Pocatello ID
107 PM MDT Fri Jul 17 2026

IDZ053-063>065-172000-
Big Hole Mountains ID-Upper Snake River Plain ID-Teton Valley ID-
Caribou Range ID-
107 PM MDT Fri Jul 17 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN TETON...SOUTH
CENTRAL FREMONT...SOUTHEASTERN JEFFERSON...NORTH CENTRAL BONNEVILLE
AND EASTERN MADISON COUNTIES THROUGH 200 PM MDT...

At 107 PM MDT, Doppler radar was tracking a strong thunderstorm 12
miles northeast of Ririe Reservoir, moving north at 20 mph.

HAZARD...Wind gusts in excess of 35 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to outdoor objects is
         possible.

Locations impacted include...
Newdale, Tetonia Research Station, and Green Canyon Hot Springs.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 4352 11142 4355 11166 4399 11163 4393 11116
TIME...MOT...LOC 1907Z 190DEG 16KT 4362 11153

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...35 MPH

KB

Special weather statement, Jul 17, 1:10 PM MDT, 4 hours 1 minute before

Special Weather Statement
National Weather Service Pocatello ID
110 PM MDT Fri Jul 17 2026

IDZ064>066-172000-
Centennial Mountains/Island Park ID-Big Hole Mountains ID-
Teton Valley ID-
110 PM MDT Fri Jul 17 2026

...A STRONG THUNDERSTORM WILL IMPACT EASTERN TETON AND SOUTHEASTERN
FREMONT COUNTIES THROUGH 200 PM MDT...

At 110 PM MDT, Doppler radar was tracking a strong thunderstorm near
Victor, or near Driggs, moving north at 20 mph.

HAZARD...Wind gusts in excess of 35 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to outdoor objects is
         possible.

Locations impacted include...
Driggs, Felt, Victor, and Tetonia.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 4359 11121 4396 11118 4394 11104 4356 11105
TIME...MOT...LOC 1910Z 190DEG 16KT 4365 11108

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...35 MPH

KB

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 16, 11:36 PM MDT	Special Weather Statement	PIH	Blaine	39 min
Jul 17, 12:19 PM MDT	Special Weather Statement	PIH	Bonneville, Madison	41 min
Jul 17, 12:46 PM MDT	Special Weather Statement	PIH	Caribou	44 min
Jul 17, 1:07 PM MDT	Special Weather Statement	PIH	Teton	53 min
Jul 17, 1:10 PM MDT	Special Weather Statement	PIH	Teton	50 min
Jul 17, 2:02 PM MDT	Flash Flood Warning	PIH	Teton	100 min
Jul 17, 5:27 PM MDT	Areal Flood Advisory	PIH	Bear Lake, Franklin	2 hr

Nearby

Flash Flood Warnings in Idaho, 2026 Every flash flood warning in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; radar from the NEXRAD Level II archive.