Significant instability, a low pressure circulation over southeastern Montana, favorable winds, and warm, moist air all combined with an approaching strong upper-level storm system to quickly develop and maintain well-organized severe thunderstorms over many locations and a macroburst in the Glendive area.
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 GGW wrote it up.
Significant instability, a low pressure circulation over southeastern Montana, favorable winds, and warm, moist air all combined with an approaching strong upper-level storm system to quickly develop and maintain well-organized severe thunderstorms over many locations and a macroburst in the Glendive area.
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 27, 2:36 PM MST, 2 hours 19 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GLASGOW MT 336 PM MDT MON JUL 27 2015 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH WEDNESDAY... A STRONG SUMMER STORM SYSTEM WILL IMPACT NORTHEAST MONTANA TONIGHT THROUGH TUESDAY EVENING. CURRENTLY THE MAIN UPPER TROUGH IS SWINGING THROUGH THE NORTHERN ROCKIES...PLACING NORTHEAST MONTANA IN A SOUTHWEST FLOW ALOFT. THE MAIN FOCUS IS FOR THUNDERSTORMS THIS EVENING...TRANSITIONING TO HEAVY SHOWERS OVERNIGHT. SHEAR AND INSTABILITY IS SUCH THAT SOME STORMS THIS EVENING COULD BE SEVERE...ESPECIALLY ALONG THE NORTH DAKOTA BORDER WHERE SHEAR AND INSTABILITY IS MORE FAVORABLE. HEAVY RAIN CONTINUES TO BE A THREAT...ESPECIALLY FOR THOSE AREAS THAT ALREADY SAW HEAVY PRECIP TOTALS LAST NIGHT...THUS THE FLOOD WATCH WAS EXPANDED TO INCLUDE VALLEY AND DANIELS COUNTIES. TUESDAY MORNING WINDS WILL QUICKLY BE ON THE UPTICK AS THE UPPER LOW DEEPENS OVER SOUTHERN SASKATCHEWAN. MODELS CONTINUE TO DEPICT WINDS REACHING 40 TO 60 MPH...THUS WENT AHEAD AND ISSUED A HIGH WIND WARNING FOR ALL OF NORTHEAST MONTANA. WINDS WILL QUICKLY DECREASE BY SUNSET ON TUESDAY AS THE STACKED SYSTEM PUSHES OUT TO THE EAST. PRECIPITATION WILL HAVE ALL BUT ENDED ACROSS MONTANA AS WELL...WITH JUST THE FAR NORTHEAST POSSIBLY SEEING SOME SHOWERS DURING THE EVENING HOURS. TUESDAY NIGHT AND WEDNESDAY WILL BE CONSIDERABLY QUIETER AS UPPER RIDGING BEGINS TO BUILD IN FROM THE WEST. .LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY... THE UPPER RIDGE REBOUNDS IN THE WEST...WHICH WILL GENERATE ZONAL TO SLIGHTLY NORTHWEST FLOW ALOFT FOR NORTHEAST MONTANA. THIS WILL BE A GENERALLY WARM AND DRY PATTERN THROUGH THE WEEKEND. ALSO CONTINUOUS DISTURBANCES IN CANADA WILL TEND TO MAINTAIN THE STATIONARY BOUNDARY OVER THE LOCAL REGION. THIS WILL KEEP THE HOT DESERT AIR TO OUR SOUTH...WHICH WILL KEEP OUR TEMPERATURES NEAR NORMAL. FEW NEEDED CHANGE TO THE EXTENDED PERIOD. SCT PREVIOUS DISCUSSION... UPPER HIGH DOMINATES OVER THE DESERT SOUTHWEST THROUGH THE EXTENDED PERIOD...WITH RIDGE EXTENDING INTO THE NORTHERN ROCKIES. UPPER LOW CURRENTLY MOVING TOWARD MONTANA STALLS OUT OVER HUDSON BAY BY THE END OF THE WEEK. THIS WILL KEEP NORTHEAST MONTANA IN SLIGHTLY NORTHWEST FLOW INTO NEXT WEEKEND. REBOUNDING RIDGE WILL BRING HOT AND DRY WEATHER BACK INTO MONTANA FOR THE END OF THE WEEK. HOWEVER JET ACROSS WESTERN CANADA WILL SUPPRESS RIDGE ENOUGH TO KEEP TEMPERATURES NEAR NORMAL. WHILE MOST OF THE MOISTURE ALSO REMAINS NORTH OF THE BORDER A FEW SHORTWAVES MOVING THROUGH THE FLOW COULD PUSH SHOWERS TOWARD THE HILINE BY THE WEEKEND BUT WILL KEEP FORECAST DRY FOR NOW. EBERT && .AVIATION... A POWERFUL STORM SYSTEM MOVES ACROSS THE NORTHERN ROCKIES TODAY THAT WILL BRING AREAS OF HEAVY RAIN...THUNDERSTORMS...SOME SEVERE...AND VERY STRONG WINDS LATE THIS AFTERNOON THROUGH TUESDAY. MOSTLY VFR THIS AFTERNOON...HOWEVER A SURFACE LOW IN NORTHEAST WYOMING WILL BRING STRONG NORTHEAST WINDS OF 25-35KT... ...THEN MVFR/IFR CONDITIONS LIKELY TONIGHT...ESPECIALLY IN THE NORTH AS THE UPPER LEVEL LOW PRESSURE SYSTEM MOVES ACROSS EASTERN MONTANA. SHOWERS AND THUNDERSTORMS WILL DEVELOP DURING THE LATE AFTERNOON AND EVENING. ...SOME STORMS MAY PRODUCE SEVERE WIND GUSTS AND/OR LARGE DAMAGING HAIL... ...THEN WIDESPREAD RAIN IS EXPECTED OVERNIGHT AND INTO TUESDAY. SOME RAIN WILL BE HEAVY. TUESDAY...VERY STRONG SUSTAINED WINDS OF 25-35G55KT...AND POSSIBLY HIGHER...ARE EXPECTED BEHIND THE SYSTEM. SCT && .GLASGOW WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING FROM 9 AM TO 9 PM MDT TUESDAY FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...DANIELS... DAWSON...EASTERN ROOSEVELT...GARFIELD...MCCONE...NORTHERN PHILLIPS...NORTHERN VALLEY...PETROLEUM...PRAIRIE...RICHLAND... SHERIDAN...SOUTHWEST PHILLIPS...WESTERN ROOSEVELT...WIBAUX. LAKE WIND ADVISORY UNTIL 9 AM MDT TUESDAY FOR FORT PECK LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY... GARFIELD...MCCONE...PETROLEUM. FLOOD WATCH THROUGH TUESDAY AFTERNOON FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...DANIELS...NORTHERN PHILLIPS...NORTHERN VALLEY...SOUTHWEST PHILLIPS. RED FLAG WARNING UNTIL MIDNIGHT MDT TONIGHT FOR MTZ122. && WEATHER.GOV/GLASGOW
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GLASGOW MT 235 PM MDT MON JUL 27 2015 MTZ016>027-059>062-281100- CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY- DANIELS-SHERIDAN-WESTERN ROOSEVELT-PETROLEUM-GARFIELD-MCCONE- RICHLAND-DAWSON-PRAIRIE-WIBAUX-NORTHERN PHILLIPS- SOUTHWEST PHILLIPS-NORTHERN VALLEY-EASTERN ROOSEVELT- 235 PM MDT MON JUL 27 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...TONIGHT A STRONG LOW PRESSURE SYSTEM WILL PUSH THROUGH NORTHEAST MONTANA TONIGHT AND TUESDAY...BRINGING A VARIETY OF WEATHER IMPACTS. A RED FLAG WARNING REMAINS IN EFFECT FOR ZONE 122 THIS EVENING. A LAKE WIND ADVISORY IS IN EFFECT FOR FORT PECK LAKE INTO TUESDAY MORNING. A FLOOD WATCH IS IN EFFECT FOR PHILLIPS...VALLEY...AND DANIELS COUNTIES FOR TONIGHT INTO TUESDAY. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY A HIGH WIND WARNING IS IN EFFECT FOR ALL OF NORTHEAST MONTANA ON TUESDAY. VERY STRONG WESTERLY WIND WILL BE PRESENT. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GLASGOW MT
336 PM MDT MON JUL 27 2015
MTZ060-272215-
PHILLIPS-
336 PM MDT MON JUL 27 2015
THE NATIONAL WEATHER SERVICE IN GLASGOW HAS ISSUED A
SIGNIFICANT WEATHER ADVISORY FOR...
SOUTHWESTERN PHILLIPS COUNTY IN NORTHEAST MONTANA...
UNTIL 415 PM MDT.
AT 334 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 21 MILES SOUTHWEST OF ZORTMAN...MOVING NORTH AT
40 MPH.
HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 50 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN.
LOCATIONS IN THE ADVISORY INCLUDE...
ZORTMAN...
THIS STORM MAY INTENSIFY...AND A SEVERE THUNDERSTORM WATCH IS IN
EFFECT FOR THIS AREA. BE CERTAIN TO MONITOR LOCAL RADIO AND TV
STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.
LAT...LON 4792 10889 4793 10864 4798 10860 4797 10830
4761 10849 4762 10871 4764 10872 4764 10877
4765 10880 4768 10879 4771 10882 4774 10890
TIME...MOT...LOC 2136Z 195DEG 36KT 4768 10876
GFF
WEATHER.GOV/GLASGOWSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GLASGOW MT
523 PM MDT MON JUL 27 2015
MTZ016-059-280030-
PHILLIPS-
523 PM MDT MON JUL 27 2015
THE NATIONAL WEATHER SERVICE IN GLASGOW HAS ISSUED A
SIGNIFICANT WEATHER ADVISORY FOR...
NORTHWESTERN PHILLIPS COUNTY IN NORTHEAST MONTANA...
UNTIL 630 PM MDT.
AT 522 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 7 MILES SOUTHWEST OF DODSON...MOVING NORTH AT 35
MPH.
HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 50 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT
DANGEROUS LIGHTNING.
LOCATIONS IN THE ADVISORY INCLUDE...
DODSON...
THIS STORM MAY INTENSIFY...AND A SEVERE THUNDERSTORM WATCH IS IN
EFFECT FOR THIS AREA. BE CERTAIN TO MONITOR LOCAL RADIO AND TV
STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.
LAT...LON 4891 10781 4824 10825 4827 10843 4844 10842
4844 10835 4857 10836 4858 10833 4874 10833
4875 10827 4891 10827 4892 10824
TIME...MOT...LOC 2323Z 193DEG 30KT 4836 10837
GFF
WEATHER.GOV/GLASGOWPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GLASGOW MT
536 PM MDT MON JUL 27 2015
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0245 AM TSTM WND GST 15 SSW SACO 48.26N 107.47W
07/27/2015 E60.00 MPH PHILLIPS MT PUBLIC
TREE BLOWN OVER.
&&
GILCHRISTPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GLASGOW MT
544 PM MDT MON JUL 27 2015
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0540 PM HAIL 14 SW HINSDALE 48.25N 107.30W
07/27/2015 E0.50 INCH VALLEY MT TRAINED SPOTTER
PEA AND DIME SIZED HAIL WITH HEAVY RAIN AND WIND GUST TO
AROUND 40 MPH.
&&
MATTMThe Glasgow radar (KGGW), 42 km away, was scanning. The volume nearest the first event began at 23:52 UTC.
17 thunderstorm wind, 9 hail. Local standard time, as filed.
Co-operative observer reported ground covered with mainly nickel-sized hail and some quarter-sized hail, along with heavy rain and winds up to 40 mph.
Trained spotter reported hail up to the size of golf balls, heavy rain, and wind gusts up to 40 mph.
Public reported quarter sized hail, lasting for 20 minutes, accumulating up to a depth of 3 inches on the ground.
Trained spotter reported 61 mph winds and heavy rain.
Trained spotter reported open front-end pole barn blown apart, an older building moved off its foundation, and broken tree limbs up to 6 inches in diameter.
The Buffalo Rapids agrimet mesonet site reported 64 mph winds.
The National Weather Service in Glasgow conducted a damage survey in Glendive on July 28, 2015 following a significant severe thunderstorm that hit the evening before coming in from the southwest. NWS staff met with county and city officials before and after the survey to be briefed and brief them on what was discovered. The event was a macroburst (large scale straight line wind event) with some microburst components in between. | There were not enough time and resources to enter the various neighborhoods that were impacted, and due to the number of trees and power lines down, it was not safe to try and go around these areas where crews were working. In order to best evaluate the wind speeds, the structures with the most damage were focused on as recommended by the Emergency Operations Center staff. Several dozen homes were viewed though, and the damage was generally due to trees and branches lost, or shingles torn off of roofs. That includes trees in homes or on cars, some partially blown off roofs, and trailer homes or semi-trailers blown over. The damage survey started with the power lines west-northwest of town on Highway 200, then to the Glendive airport, Seven Mile Drive, back through town on Highway 200S, up Merrill Ave and then up Highway 16 north to Sidney for 10 miles. | Access to the large metal truss electrical transmission towers west-northwest of town on Highway 200S was not possible due to the extreme mud conditions. There were at least 5 noted as having crumbled toward the ground. Further investigation will have to be done with the owner of the structures as to the age of these towers, but at minimum the winds would’ve been 120 mph. There are also numerous wooden poles snapped at the bases and part way up along Highway 200. The NWS will get total numbers from utility providers once they have a chance to assess all the damage. |At the airport, winds were gusting to 90 mph last night on an anemometer on top of the terminal roof. The winds tore the anemometer off the roof though, so a peak wind was not measured. The FAA AWOS station that is the official observing equipment for the airport lost power, and a maximum gust was not received from it either. There was a large cottonwood tree that was uprooted near the terminal building. There were three metal roof/siding airplane hangars damaged. One was completely destroyed, and the other two had the metal roofing peeled back/off. The one that was destroyed wasn’t cemented into the ground and the posts easily ripped out of the ground when the wind blew against it. All the debris was blown towards the north-northeast. The winds are estimated at 90 to 95 mph at this location. |The next stop was on Highway 200S just southeast of the Interstate turnoff. Significant damage occurred to a large metal building. The failure point was two large garage doors that face southwest. There is nothing to stop the wind as it rolls through the valley towards it. The garage doors blew in, and the roof blew off. One of the employees mentioned that sheet metal from another building southwest of them was blown towards their building. The impact of that metal hitting the doors may have helped cause the doors to fail and be blown in. This metal building had solid steel I-Beams in the ceiling that were bent back where the roof peeled back. Power poles with transformers on them were snapped off near this facility and just east-southeast of it. The transformers are pretty heavy and the resistance and weight of them against the wind made them easy targets to be snapped. All the debris was blown in a north-northeasterly direction. Between the building and the power poles, winds at this location are estimated to have been around 100 to 110 mph.|7 Mile Drive was next. There were many homes with shingles peeled off, and large trees split and large branches down, metal buildings damaged and sheet metal blown around. A few power poles were also snapped. We stopped at an office building and a newer, well-built warehouse after noticing the garage doors on the warehouse were bent out. There was also some insulation missing on a portion of a wall. They had already cleaned up the south side doors, which had blown in as the winds came off the hill and crumbled some of the north side doors. There was very little noticeable roof damage, which is something you will often see with garage doors blowing in, a testament to how well the building was built and the steel I-beams used in the trusses. Winds at this location are estimated at 100-105 mph. |Another metal building structure was viewed south of the interstate off of 7 Mile Drive. A large overhead door that faces south was blown in and the roof right above it peeled off and blown to the north. On the north side of the building, the majority of the roof (with wooden trusses) was either collapsed into the building or blown north-northeastward. Winds at this location are estimated at 95 to 100 mph.|As we went down Highway 200S into downtown, the most notable damage was tree branches down. We went down Marsh Road, and there were a lot of trees damaged in that area from 1 to 3 miles south of town. House damage was generally due to branches falling on them or against them. Heading north on Merrill Ave, tree damage was the most noticed damage, specifically near the high school football field. A large blue spruce was noted down near I-94 and roof damage with shingles and fascia torn off were noted on a new hotel at that location. Winds in this portion of town are estimated to have been 80-90 mph. |We continued north on Highway 16 towards Sidney. The number of damaged trees and sheds quickly reduced as we headed north and by 10 miles we were really looking hard to see any damage. At four miles north of town, there was a home with a new barn that had all but the west wall collapse. With no one home, we did not go out into the field to assess the barn closer, but it was newly built. Winds at this point are estimated at 100 mph.
Glendive Airport had a supplementary wind sensor that measured a 90 mph wind gust before the anemometer failed and blew off the roof.
Co-operative observer reported small amounts of hail up to the size of nickels and wind gusts up to 36 mph.
Bloomfield mesonet site measured 75 mph winds.
Trained spotter reported damaged buildings and grain bins tipped over from 80 mph winds.
Public reported quarter-sized hail.
Public reported quarter-sized hail and heavy rain.
Trained spotter reported quarter-sized hail with heavy rain sometime between 7:30 and 8:00 PM local time.
Mesonet site west of Wolf Point measured 72 mph winds.
Trained spotter reported nickel-sized hail.
Trained spotter reported wind gusts up to 65 mph.
Trained spotter reported a roof blown off an old shed due to 60 mph wind gusts.
Trained spotter reported 60 mph winds with rain.
US-2 Stateline DOT site measured sustained winds of 46 mph and gusts up to 60 mph.
Public reported 63 mph winds.
Public reported 85 mph winds.
Trained spotter reported quarter-sized hail with heavy rain.
Comertown Turn-Off MT-5 DOT site measured 64 mph winds.
Trained spotter reported 60 mph winds.
Trained spotter reported 70 mph winds.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2015Every state in 2015This day in weather historyWarnings in Montana, July 2015
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: 596106, 596117, 596118, 596120, 596119, 596121, 597453, 596123, 596137, 596127, 596125, 596128, 596130, 596135, 596136, 596138, 596139, 596140, 596141, 596142, 596143, 596144, 596146, 596147, 596148, 596149.