Flash Flooding and Hail in Montana, May 26 to 27, 2019

Name: Flash Flooding and Hail in Montana, May 26 to 27, 2019
Start: 2019-05-26T14:41
End: 2019-05-27T03:00
Location: Montana

May 26 to 27, 2019 · NWS BYZ · 9 events in 5 counties and zones

A strong jet streak moved over the forecast area during the late afternoon into the evening hours on the 26th. This jet streak provided for strong upper level divergence.

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 9

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS BYZ wrote it up.

A strong jet streak moved over the forecast area during the late afternoon into the evening hours on the 26th. This jet streak provided for strong upper level divergence. |At the same time, a strong upper level disturbance moved over the forecast area. |All the above, combined with low-level moisture and wind shear, resulted in severe thunderstorms across portions of the Billings Forecast area.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Billings, MT wrote its last area forecast discussion before the first event at May 26, 2:09 PM MST, 32 minutes earlier.

Area forecast discussion, May 26, 2:09 PM MST, 32 minutes before

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Hazardous weather outlook, May 26, 4:28 AM MST, 10 hours 13 minutes before

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In the hours before

Local storm report, May 26, 11:08 AM MST, 3 hours 33 minutes before

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Special weather statement, May 26, 12:59 PM MST, 1 hour 42 minutes before

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Local storm report, May 26, 1:31 PM MST, 1 hour 10 minutes before

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Special weather statement, May 26, 1:57 PM MST, 44 minutes before

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Special weather statement, May 26, 2:24 PM MST, 17 minutes before

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The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

7 hail, 2 flash flood. Local standard time, as filed.

Hail, Park

When: May 26, 2:41 PM MST
Where: Park County, 4.26 mi SSE of Livingstn Mission Fl
Measured: 1 in hail
Reported by: CoCoRaHS
Coordinates: 45.640, -110.430

Hail, Carter

When: May 26, 2:51 PM MST
Where: Carter County, 2.81 mi ESE of Alzada
Measured: 2 in hail
Reported by: Public
Coordinates: 45.000, -104.370

Hail, Stillwater

When: May 26, 3:30 PM MST
Where: Stillwater County, 0.96 mi E of Rapelje
Measured: 1.5 in hail
Reported by: COOP Observer
Coordinates: 45.970, -109.250

Flash Flood, Stillwater

When: May 26, 7:00 PM MST to 11:00 PM MST
Where: Stillwater County, 1.16 mi SE of Rapelje to 1.04 mi SE of Rapelje
Cause: Heavy Rain
Reported by: COOP Observer
Coordinates: 45.957, -109.254

Sixshooter Creek in Rapelje flooded up to a foot deep and 200 yards wide over Highway 306.

Hail, Yellowstone

When: May 26, 8:08 PM MST
Where: Yellowstone County, 5.63 mi NNE of Billings Hgts
Measured: 1.75 in hail
Reported by: Trained Spotter
Coordinates: 45.890, -108.460

Hail, Yellowstone

When: May 26, 8:10 PM MST
Where: Yellowstone County, 0.69 mi S of Laurel
Measured: 1 in hail
Reported by: Public
Coordinates: 45.670, -108.770

Hail, Yellowstone

When: May 26, 8:12 PM MST
Where: Yellowstone County, 6.24 mi NNE of Billings Hgts
Measured: 1.25 in hail
Reported by: Trained Spotter
Coordinates: 45.900, -108.460

Hail, Yellowstone

When: May 26, 8:16 PM MST
Where: Yellowstone County, 6.39 mi WSW of Shepherd
Measured: 1.75 in hail
Reported by: Public
Coordinates: 45.910, -108.470

Flash Flood, Big Horn

When: May 26, 10:00 PM MST to May 27, 3:00 AM MST
Where: Big Horn County, 11.17 mi NE of Pryor to 5.01 mi W of Hardin
Cause: Heavy Rain
Reported by: Public
Coordinates: 45.526, -108.345

A nearly stationary thunderstorm was situated over portions of western Big Horn County during the late evening hours on the 26th into the early morning hours of the 27th. Several inches of rain fell across this area within just a few hours. Flash flooding occurred on Pryor, Fly and Woody Creeks which resulted in damage to roads and bridges. Culverts were also displaced. Damage to trap and skeet field buildings at a fishing and shooting club was also reported.

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Montana in 2019 Every state in 2019 This day in weather history Warnings in Montana, May 2019

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-30. Each event’s entry at NCEI: 818408, 818409, 818410, 819880, 818411, 818412, 818416, 818413, 820153.