Several thunderstorms developed via daytime heating of the Rockies, near Glacier National Park, during the late afternoon of July 25th. As these storms tracked southeastward, they congealed into a cluster as their cold pools merged and interacted with ambient low-level vertical shear, resulting in the repeated formation of new storms along the downshear flank of the cold pool amidst moderate to…
Every event with a place to put it. Tap one for its entry below.
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.
The episode as NWS TFX wrote it up.
Several thunderstorms developed via daytime heating of the Rockies, near Glacier National Park, during the late afternoon of July 25th. As these storms tracked southeastward, they congealed into a cluster as their cold pools merged and interacted with ambient low-level vertical shear, resulting in the repeated formation of new storms along the downshear flank of the cold pool amidst moderate to strong effective bulk shear and weak to moderate instability. At one point, this thunderstorm cluster was a well-developed bow echo. These storms produced damaging wind gusts and hail up to quarter-size over portions of north-central MT during the evening of the 25th.
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 Great Falls, MT wrote its last area forecast discussion before the first event at Jul 25, 5:05 PM MST, 2 hours 38 minutes earlier.
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</html>Special Weather Statement
National Weather Service Great Falls MT
655 PM MDT WED JUL 25 2018
MTZ009-260145-
Northern Rocky Mountain Front MT-
655 PM MDT WED JUL 25 2018
...SIGNIFICANT WEATHER ADVISORY FOR WEST CENTRAL PONDERA AND SOUTH
CENTRAL GLACIER COUNTIES UNTIL 745 PM MDT...
At 654 PM MDT, Doppler radar was tracking a strong thunderstorm near
Kiowa, or 46 miles west of Cut Bank, moving southeast at 20 mph.
Dime size hail and wind gusts up to 50 mph will be possible with this
storm.
Locations impacted include...
Kiowa, East Glacier Park Village, East Glacier Park and South
Browning.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.
&&
LAT...LON 4858 11329 4851 11282 4848 11279 4820 11319
4835 11337 4837 11334 4842 11335 4842 11340
4845 11347
TIME...MOT...LOC 0054Z 313DEG 17KT 4847 11331
mpjSpecial Weather Statement National Weather Service Great Falls MT 702 PM MDT WED JUL 25 2018 MTZ010-044-046-260145- Eastern Glacier MT-Eastern Pondera MT-Toole MT- 702 PM MDT WED JUL 25 2018 ...SIGNIFICANT WEATHER ADVISORY FOR NORTH CENTRAL PONDERA...EAST CENTRAL GLACIER AND SOUTHWESTERN TOOLE COUNTIES UNTIL 745 PM MDT... At 701 PM MDT, Doppler radar was tracking a strong thunderstorm 9 miles west of Cut Bank, moving southeast at 15 mph. Dime size hail and wind gusts up to 50 mph will be possible with this storm. Locations impacted include... Cut Bank and Ethridge. PRECAUTIONARY/PREPAREDNESS ACTIONS... To report severe weather, contact your nearest law enforcement agency. They will relay your report to the National Weather Service office in Great Falls. && LAT...LON 4859 11270 4873 11254 4856 11207 4834 11230 TIME...MOT...LOC 0101Z 304DEG 15KT 4863 11253 mpj
The Great Falls radar (KTFX), 88 km away, was scanning. The volume nearest the first event began at 02:41 UTC.
7 thunderstorm wind, 1 hail. Local standard time, as filed.
COOP observer 2-miles SSE of Bynum estimated peak gust of 80 mph and quarter-size hail with the passage of a thunderstorm. Significant damage to crops occurred.
Estimated peak gust of 60 mph near Bynum. Lots of pea-size hail and rain.
Up to quarter-size hail accumulated to a depth of several inches in Bynum. Crops ruined.
Estimated peak gusts of 65 mph. Large trees knocked down in multiple locations in Choteau.
Delayed report of multiple trees down and no power in Choteau. Also reported pea-size hail. Estimated peak gusts of 60 mph. Time of report estimated via radar.
Good-sized tree branches down 6-miles WSW of Cascade. Winds blew door off its hinges.
Trained spotter reported 59 mph peak gust from thunderstorm 8-miles SSE of Ulm.
A 59 mph peak gust from a thunderstorm was reported 3-miles south of Sun Prairie.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2018Every state in 2018This day in weather historyWarnings in Montana, July 2018
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: 760396, 760398, 760397, 760399, 760400, 760401, 760402, 760403.