Yellowstone National Park, Wyoming

Regional Weather Alerts


     

Alert: Severe Thunderstorm Warning
Area(s): Lewis and Clark, MT; Teton, MT
Effective: 2026-07-17 @ 3:51 pm -> 2026-07-17 @ 4:45 pm
Onset: 2026-07-17 @ 3:51 pm -> 2026-07-17 @ 4:45 pm
Severity: Severe
Certainty: Observed
Urgency: Immediate
Issued By: NWS Great Falls MT on 2026-07-17 @ 3:51 pm
Headline: Severe Thunderstorm Warning issued July 17 at 2:51PM MDT until July 17 at 3:45PM MDT by NWS Great Falls MT
Description: SVRTFX

The National Weather Service in Great Falls has issued a

* Severe Thunderstorm Warning for...
Northwestern Lewis and Clark County in west central Montana...
Southwestern Teton County in north central Montana...

* Until 345 PM MDT.

* At 250 PM MDT, a severe thunderstorm was located 16 miles northwest
of Augusta, or 30 miles southwest of Choteau, moving east at 15
mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage
to roofs, siding, and trees.

* Locations impacted include...
Augusta, Pishkun Reservoir, and Nilan Reservoir.

Alert: Flash Flood Warning
Area(s): Park, MT; Sweet Grass, MT
Effective: 2026-07-17 @ 3:16 pm -> 2026-07-17 @ 6:15 pm
Onset: 2026-07-17 @ 3:16 pm -> 2026-07-17 @ 6:15 pm
Severity: Severe
Certainty: Likely
Urgency: Immediate
Issued By: NWS Billings MT on 2026-07-17 @ 3:16 pm
Headline: Flash Flood Warning issued July 17 at 2:16PM MDT until July 17 at 5:15PM MDT by NWS Billings MT
Description: FFWBYZ

The National Weather Service in Billings has issued a

* Flash Flood Warning for...
Central Park County in south central Montana...
West Central Sweet Grass County in south central Montana...

* Until 515 PM MDT.

* At 216 PM MDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 1 and 2 inches of rain
have fallen. Additional rainfall amounts of 0.5 to 1 inch are
possible in the warned area. Flash flooding is ongoing or expected
to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar indicated.

IMPACT...Flash flooding of small creeks and streams, including the
Boulder River south of Mc Leod, as well as other poor
drainage and low-lying areas.

* Some locations that will experience flash flooding include...
Mainly rural areas of Central Park and West Central Sweet Grass
Counties.

Alert: Special Weather Statement
Area(s): Southern Rocky Mountain Front; Southern High Plains
Effective: 2026-07-17 @ 3:14 pm -> 2026-07-17 @ 4:15 pm
Onset: 2026-07-17 @ 3:14 pm
Severity: Moderate
Certainty: Observed
Urgency: Expected
Issued By: NWS Great Falls MT on 2026-07-17 @ 3:14 pm
Headline: Special Weather Statement issued July 17 at 2:14PM MDT by NWS Great Falls MT
Description: At 213 PM MDT, Doppler radar was tracking a strong thunderstorm 29
miles northwest of Augusta, or 36 miles west of Choteau, moving
northeast at 20 mph.

HAZARD...Wind gusts of 50 to 55 mph and half-inch size hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Pishkun Reservoir.

Alert: Flash Flood Watch
Area(s): Big Belt, Bridger and Castle Mountains
Effective: 2026-07-17 @ 1:23 am -> 2026-07-18 @ 1:00 am
Onset: 2026-07-17 @ 1:23 am -> 2026-07-18 @ 1:00 am
Severity: Severe
Certainty: Possible
Urgency: Future
Issued By: NWS Great Falls MT on 2026-07-17 @ 1:23 am
Headline: Flash Flood Watch issued July 17 at 12:23AM MDT until July 18 at 12:00AM MDT by NWS Great Falls MT
Description: * WHAT...Flash flooding and debris flows caused by excessive rainfalL
will be possible over the Horse Gulch Burn Scar this afternoon and
evening.

* WHERE...A portion of central Montana, including the following
areas, portions of southeast Lewis and Clark County and northwest
Meagher County.

* WHEN...Through this evening.

* IMPACTS...Localized heavy rainfall from thunderstorms is expected
over the Horse Gulch Burn Scar this afternoon and evening.
Residents near the Horse Gulch Burn Scar should prepare for
potential debris flows and flash flooding.

* ADDITIONAL DETAILS...
- Scattered to numerous showers and thunderstorms will be capable
of producing heavy rainfall over the burn scar, which may lead to
flash flooding and debris flows.
- Some locations that may experience flash flooding include...
Areas over and near the Horse Gulch Burn scar
- http://www.weather.gov/safety/flood