Montana, 2018Tornado and Hail in Montana, July 9, 2018
July 9, 2018 · NWS GGW · 7 events in 1 county or zone
A powerful shortwave trough combined with a moderately unstable air mass, producing showers and thunderstorms across the region. A few of these became severe in the evening, especially as the trough interacted with areas of higher dewpoints close to the North Dakota and Saskatchewan borders.
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
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 7
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.
A powerful shortwave trough combined with a moderately unstable air mass, producing showers and thunderstorms across the region. A few of these became severe in the evening, especially as the trough interacted with areas of higher dewpoints close to the North Dakota and Saskatchewan borders. The most significant storms were the supercells which impacted Sheridan County, bringing significant damage to the Plentywood area in the form of a macroburst and an EF-1 tornado.
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 Jul 9, 1:33 PM MST, 4 hours 32 minutes earlier.
Area forecast discussion, Jul 9, 1:33 PM MST, 4 hours 32 minutes before
Area Forecast Discussion
National Weather Service Glasgow MT
233 PM MDT Mon Jul 9 2018
.DISCUSSION...
A strong upper-level ridge of high pressure air occupies much of
the west. The ridge axis will run over NE MT tonight. A storm
system off the Pac-NW coast will ride over the ridge tonight,
affecting our area Tuesday with strong storms. Today and evening,
there is a warm front over the area with good lapse rates and
cape in place. Thunderstorms are expected to develop along this
boundary, much of it in Saskatchewan. The areas of greatest
concern for strong storms is our northeast corner. The model
sounding shows vertical shear, and southeast surface flow to keep
the humidity higher in eastern zones.
Tuesday, our area has again been highlighted for Severe
Thunderstorms, this time Slight Risk. Again the strongest storms
may run east, north of the border, but produce storms mainly
across our northern zones, beginning in the late afternoon and
evening. Again, lapse rates and cape indicate a very unstable
environment. However in this case, the storm system brings a cold
front to set off storms.
Besides the storms, Tuesday is expected to be another hot day,
with highs around 100 again in some locations. With temperatures
again expected to rise into the high 90s and possibly triple
digits, heat risk again becomes an issue. Issued a Heat Advisory
for portions of the area. Also, with the expected wind and dry
conditions in Northern Valley & Phillips Counties, fire wx has
become a concern, especially based on the Drought Monitor
indicating Slight Drought conditions for those areas. Templer
Previous Discussion for Wednesday and Beyond:
Temperatures cool about 15 degrees behind the front on Wednesday
as the upper trof moves through central Canada. Westerly flow
will keep the region dry, as temperatures slowly rebound.
By the end of the week, the next trof will drop into western
Canada. Cold front passage expected Friday night with
thunderstorms delayed until Saturday night, but confidence is not
high. Ebert
&&
.AVIATION...
Mainly VFR conditions expected over the next 24 hours.
A warm front could produce isolated thunderstorms that could
impact the TAF sites intermittently this afternoon, and tonight.
Some storms may become severe.
Tuesday, after a hot day, a cold front pushes through the area to
produce thunderstorms, some possibly severe, and strong wind.
Wind: east-southeast 10-20G30kt, becoming 10kt or less after
midnight. Wind will shift to the NW behind the cold front Tuesday
evening
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from noon to 8 PM MDT Tuesday for Central and
Southeast Phillips...Central and Southern Valley...Garfield...
McCone...Southwest Phillips...Western Roosevelt.
&&
weather.gov/glasgow
Event by event
3 thunderstorm wind, 3 hail, 1 tornado. Local standard time, as filed.
Thunderstorm Wind, Sheridan
- When
- July 9, 6:05 PM MST
- Where
- Sheridan County, 0.83 mi NNE of Plentywood Shrwd Arp
- Measured
- 103 kt (119 mph) estimated gust
- Reported by
- NWS Storm Survey
- Coordinates
- 48.790, -104.520
The town of Plentywood was directly hit by a macroburst with estimated wind speeds of up to 118 mph. The most significant damage occurred at the Plentywood airport, where the metal beacon tower was bent over to the ground, ten general aviation aircraft were damaged or destroyed, eight hangars were totaled, and 6 other hangars sustained minor to moderate damage. Widespread tree and roof damage was reported throughout the town, along with a couple of outbuildings and garages destroyed.
Tornado, Sheridan
- When
- July 9, 6:05 PM MST to 6:09 PM MST
- Where
- Sheridan County, 0.68 mi S of Plentywood Shrwd Arp to 2.57 mi SE of Plentywood Shrwd Arp
- Rating
- EF1
- Path length
- 2.1 mi
- Path width
- 250 yd
- Reported by
- NWS Storm Survey
- Coordinates
- 48.770, -104.531
A short-lived, EF-1 tornado, with maximum estimated wind speeds of 110 mph moved nearly along Highway 16, on the southeast side of Plentywood.
Hail, Sheridan
- When
- July 9, 6:11 PM MST
- Where
- Sheridan County, 1.45 mi SSW of Plentywood Shrwd Arp
- Measured
- 1 in hail
- Reported by
- Trained Spotter
- Coordinates
- 48.760, -104.540
Trained spotters reported hail up to the size of quarters.
Hail, Sheridan
- When
- July 9, 6:40 PM MST
- Where
- Sheridan County, 7.65 mi N of Dagmar
- Measured
- 1.5 in hail
- Reported by
- Public
- Coordinates
- 48.690, -104.180
Public reported ping pong ball size hail.
Thunderstorm Wind, Sheridan
- When
- July 9, 6:45 PM MST to 7:05 PM MST
- Where
- Sheridan County, 5.63 mi ESE of Reserve
- Measured
- 75 kt (86 mph) measured gust
- Reported by
- Mesonet
- Coordinates
- 48.556, -104.347
The Director of the North Dakota Agricultural Weather Network (NDAWN) reported through social media that the agrimet mesonet site Dagmar 7WSW measured wind gusts of at least 65 mph from 6:45 PM MST to 7:05 PM MST. The peak wind gust of 86 mph was recorded at 7:00 PM MST. All times are estimated.
Thunderstorm Wind, Sheridan
- When
- July 9, 7:41 PM MST
- Where
- Sheridan County, 0.69 mi N of Medicine Lake Raws
- Measured
- 60 kt (69 mph) measured gust
- Reported by
- RAWS
- Coordinates
- 48.490, -104.480
The Medicine Lake RAWS site measured a 69 mph wind gust. Time is estimated.
Hail, Sheridan
- When
- July 9, 7:55 PM MST
- Where
- Sheridan County, 0.91 mi E of Plentywood
- Measured
- 1.75 in hail
- Reported by
- COOP Observer
- Coordinates
- 48.780, -104.550
Multiple co-operative observers reported hail up to the size golf balls.
- Thunderstorm Wind
- Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
- Tornado
- A violently rotating column of air in contact with the ground and extending from a thunderstorm, filed with its path, width and Fujita or Enhanced Fujita rating from the damage survey.
- Hail
- Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
After NWS Directive 10-1605, the rules offices file Storm Data by.
- Tornado and Hail in North Dakota, July 9 to 10, 20181 death · 28 injured · $3.5 million · EF2 · 16 events
- Flash Flood and Hail in Arizona, July 9, 20182 injured · $242,000 · 78 kt wind · 27 events
- Flash Flooding in Utah, July 9 to 13, 2018$325,000 · 10 events
- Dust Storm in California, July 9, 2018$200,000 · 1 event
- Flash Flood and Damaging Winds in Nevada, July 9, 2018$63,000 · 65 kt wind · 5 events
- Flash Flooding and Flooding in Puerto Rico, July 9 to 15, 2018$2,000 · 12 events
- Dust Storm in Arizona, July 9, 20187 events
- Hail and Damaging Winds in South Dakota, July 9, 20181 in hail · 6 events
- Hail and Damaging Wind in Wyoming, July 9, 20181.5 in hail · 4 events
- Dust Storm and Damaging Winds in Arizona, July 9, 201854 kt wind · 4 events
- Damaging Winds in Arizona, July 9, 2018$11,000 · 52 kt wind · 2 events
- Damaging Winds in South Dakota, July 9, 201852 kt wind · 3 events
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: 770377, 770409, 770411, 770412, 770371, 770424, 770413.