Flood and Heavy Rain in Montana, August 23, 2019

Name: Flood and Heavy Rain in Montana, August 23, 2019
Start: 2019-08-23T09:55
End: 2019-08-23T11:45
Location: Montana

August 23, 2019 · NWS GGW · 6 events in 2 counties and zones

An unstable atmosphere and decent low-level moisture combined to produce some strong thunderstorms, some of which brought some heavy rain to portions of northeast Montana.

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

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The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 6

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 GGW wrote it up.

An unstable atmosphere and decent low-level moisture combined to produce some strong thunderstorms, some of which brought some heavy rain to portions of northeast Montana.

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 Glasgow, MT wrote its last area forecast discussion before the first event at Aug 23, 8:15 AM MST, 1 hour 40 minutes earlier.

Area forecast discussion, Aug 23, 8:15 AM MST, 1 hour 40 minutes before

Area Forecast Discussion
National Weather Service Glasgow MT
915 AM MDT Fri Aug 23 2019

.DISCUSSION...
Upper low centered near Yellowstone National Park this morning is
expected to lift NE today and weaken. This will keep the threat
of showers/tstorms today, especially northern and eastern border
areas. Temps today will be noticeably cooler, but humidity is high
too. TFJ

Previous Discussion...
Cold front was located near Scobey, Wolf Point, and Glendive at 2
am MDT (08Z). This front will become quasi- stationary along the
MT/Dakota this morning and remain there and gradually weaken today
and dissipate tonight. Meanwhile, an upper trough will drift east
across Montana and Wyoming today and tonight. Showers and
thunderstorms to the west of the front are expected to diminish
this morning. Then, more showers and thunderstorms are possible in
the eastern half of the forecast area this afternoon and tonight.
At this point, the best instability stays to the south of the
forecast area which will limit the possibility of severe weather
over NE Montana today and tonight.

Temperatures will be 10 to 15 degrees cooler across the forecast
area today.

The upper trough drifts to the east on Saturday. A shortwave
trough moves along the MT/Canada border with a weak cold front
which could produce some showers and thunderstorms. A stronger
wave follows Saturday Night and Sunday with a cold front on Sunday
which will bring a good chance for more showers and thunderstorms.

An unstable NW flow aloft is expected on Monday and Tuesday with
cool temperatures and chances for showers and thunderstorms.

A drier NW flow aloft will prevail the remainder of the week with
temperatures staying below normal. Forrester

&&

.AVIATION...

FLIGHT CAT: VFR-MVFR.

DISCUSSION: A cold front will be quasi-stationary near the
MT/Dakota border today and tonight with showers and thunderstorms
at times. Otherwise, there will be a mix of low and mid level
clouds today and tonight with some breaks in the clouds at times.
The low clouds could produce MVFR ceilings at times.

WIND: Mainly north to northwest around 10 knots today at KGGW and
KOLF. Variable less than 10 knots at KGDV and KSDY today. Winds
will be light and variable tonight.

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

weather.gov/glasgow

The radar

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

Open the radar archive at this moment

Event by event

5 heavy rain, 1 flood. Local standard time, as filed.

Heavy Rain, Garfield

When: August 23, 9:55 AM MST
Where: Garfield County, 5.61 mi N of Brusett
Reported by: Social Media
Coordinates: 47.430, -107.270

Public reported, via social media, a 24-hour rainfall total of 3.75 inches.

Heavy Rain, Valley

When: August 23, 9:55 AM MST
Where: Valley County, 7.82 mi SE of Nashua
Reported by: Social Media
Coordinates: 48.050, -106.230

Public reported, via social media, a 24-hour rainfall total of 3.00 inches.

Heavy Rain, Valley

When: August 23, 9:55 AM MST
Where: Valley County, 0.46 mi W of Nashua
Reported by: Social Media
Coordinates: 48.130, -106.360

Public reported, via social media, a 24-hour rainfall total of 3.10 inches.

Heavy Rain, Valley

When: August 23, 9:55 AM MST
Where: Valley County, 0.46 mi W of Tampico
Reported by: Public
Coordinates: 48.300, -106.830

Public reported a 24-hour rainfall total of 4.00 inches.

Heavy Rain, Valley

When: August 23, 9:55 AM MST
Where: Valley County, 2.4 mi ESE of Vandalia
Reported by: COOP Observer
Coordinates: 48.340, -106.850

Cooperative observer reported a 24-hour rainfall total of 3.60 inches.

Flood, Valley

When: August 23, 11:45 AM MST
Where: Valley County, 4.74 mi NNE of Vandalia to 5.02 mi NNE of Vandalia
Cause: Heavy Rain
Reported by: Emergency Manager
Coordinates: 48.410, -106.850

Valley County DES Coordinator reported a 150-foot stretch of dirt road along Bear Creek Road was washed out.

What these are

Heavy Rain: Rainfall totals unusual for the place and season that did not produce a flood.
Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

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, August 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 2026-09-24. Each event’s entry at NCEI: 844153, 844154, 844155, 844156, 844157, 844152.