Large scale upper level troughing with two separate embedded upper level lows progressed across the region late June. The colder core, which actually ended up being the southern of the two, moved across Southwest Montana and resulted in snow levels falling to below 6,000ft at times as heaviest precipitation moved over the area.
Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. 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.
Large scale upper level troughing with two separate embedded upper level lows progressed across the region late June. The colder core, which actually ended up being the southern of the two, moved across Southwest Montana and resulted in snow levels falling to below 6,000ft at times as heaviest precipitation moved over the area. Heavy snow developed near and above pass level in northwest Beaverhead County, resulting in nearly 2 feet of snow near the peaks close to the ID border.
Meanwhile further north under the second upper low, a strong surface low ended up developing near the Hi-Line, which resulted in strong winds in a few zones before the surface low filled/weakened.
Strong upper level support further north resulted in widespread heavy rains, with additional upslope forcing along the Rocky Mountain Front, which resulted in some flooding in Glacier NP June 29.
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 Jun 27, 11:01 PM MST, 59 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Great Falls MT 1201 AM MDT Sun Jun 28 2026 Aviation Section Updated. .KEY MESSAGES... - Transition to a cooler system begins this afternoon, with lower elevation rain and higher elevation snow becoming more widespread across Southwest Montana this evening. - Better precipitation arrives across North-central Montana, particularly west of I-15, Sunday evening. - Precipitation gradually moves out late Monday, though unsettled conditions remain through the remainder of the week. && .DISCUSSION... /Issued 539 PM MDT Sat Jun 27 2026/ Large scale upper level troughing will bring a couple waves of precipitation to the region over the next few days. The initial push of better precipitation arrives through the remainder of the day and tonight, primarily across Southwest Montana into portions of Central Montana. Snow levels fall with the arrival of the coolest air aloft, dropping down to as low as 6,000 ft or so at times, lowest south of I-90. Brief spurts of snow levels lower than 6,000ft will not be unreasonable given the precipitation rates that look to exist as convective elements slowly transition to be more stratiform in nature. As the initial core of the upper level low fills across Southwest Montana into Sunday, deepening within the troughing looks to ensue further north across North-central Montana. A closed mid-level low looks to develop somewhere over northern Montana as a result, and gradually nudge back westward during the day Sunday. This will result in not only a favorably forced environment from a dynamical perspective over the plains, but there will be some upslope enhancement as northerly or northeasterly flow on the western side of the mid level flow interacts with terrain. All this to say there looks to be a favorable regime for widespread precipitation over North-central Montana beginning Sunday afternoon, but peaking Sunday night into early Monday before gradually diminishing. Peak precipitation amounts will follow where the best forcing ultimately settles, but also occur in upslope favored areas along the Rocky Mountain Front. The overall orientation of terrain favors the Northern Rocky Mountain Front over the southern ever so slightly for greater precipitation amounts. A flood watch remains in effect for areas in and near the eastern side of Glacier NP east of the Continental Divide. A surface low looks to follow a similar track as the aforementioned mid level low Sunday into Monday. As this occurs, gusty winds look to develop over the plains. While the overall magnitude of these winds/gusts is not particularly notable for the region, the time of the year and direction of the stronger winds (Direction will vary quite a bit, dependent on where the surface low tracks with respect to any given area) does look to be a bit abnormal, which may pose greater impacts. The upper level disturbance moves out into Tuesday, though a lingering southwesterly flow aloft and general troughing across the west will keep afternoon and evening showers and thunderstorms in the forecast for much of the remainder of the week. -AM && .AVIATION... 28/06Z TAF Period Widespread showers and thunderstorms will remain a threat through the TAF period with periods of MVFR/IFR conditions possible. Mountain obscuration will be a concern through the entire period across the region. -thor && .HYDROLOGY... Periods of rain will affect the CWA from today through Monday. Widespread rainfall amounts of 1 to 3 inches are expected across the CWA over the next 3 days. In the Glacier Park region, rainfall could be a bit heavier, possibly up to 4 inches. Additionally, with some high elevation snow still left, the combination of rainfall/snowmelt could lead to some flooding on the east side of Glacier National Park. Thus a flood watch has been issued for this region starting on Sunday. Additional flood statement might be needed if rainfall amounts start to exceed 3 inches elsewhere across the CWA. Brusda && .PRELIMINARY POINT TEMPS/POPS... GTF 49 58 46 59 / 90 90 90 100 CTB 49 63 48 60 / 60 90 100 100 HLN 46 54 45 57 / 100 100 100 100 BZN 41 52 39 55 / 100 100 90 100 WYS 32 48 29 48 / 90 90 90 100 DLN 38 50 37 56 / 100 90 90 90 HVR 50 67 47 66 / 80 100 90 90 LWT 44 55 41 57 / 90 90 80 90 && .TFX WATCHES/WARNINGS/ADVISORIES... Flood Watch from Sunday evening through Tuesday morning for East Glacier Park Region. Winter Weather Advisory until noon MDT Monday for Elkhorn and Boulder Mountains-Gallatin and Madison County Mountains and Centennial Mountains-Ruby Mountains and Southern Beaverhead Mountains. Winter Storm Warning until noon MDT Monday for Northwest Beaverhead County. && http://www.weather.gov/greatfalls
The national radar mosaic for the moment the first event began.
2 high wind, 1 heavy snow, 1 flood. Local standard time, as filed.
Snotel equipment in this zone, including at Lemhi Ridge, Darkhorse Lake, and Slagamelt Lakes estimated new snow in excess of 9 inches, including a peak snow depth change of 21 inches at Darkhorse Lake by 6 AM Monday the 29th.
Several mesonets measured gusts in excess of 58 mph, including DW4821 Chester, DW4776 Chester, GW0625 Joplin 17 North, GW3546 WHITLASH SEVEN SOUTH, GW0718 Joplin 25nnw, and MTM53 MDA Oilmont. The peak observed gust was 64 mph at DW4821 Chester.
ASOS station KHVR Havre Airport measured a 70 mph gust. Other sensors in this zone that measured a 58+ mph gust include EW1937 Goldstone and FW1664 Hingham.
Late morning June 29 reports were received that water in Swiftcurrent Lake was approaching the bottom of the bridge connecting Many Glacier Hotel to Many Glacier Road, and that several trails and campsites had already been closed in the Many Glacier Valley due to flooding from heavy rain and a small contribution from snowmelt. Many Glacier Hotel was ultimately evacuated after MBRFC forecast crest information was received. Numerous trails were closed in the Many Glacier Valley, with it being noted that water was flowing down several trails.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2026Every state in 2026This day in weather historyWarnings in Montana, June 2026
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: 1345693, 1345695, 1345694, 1345702.