Scattered thunderstorms developed over the area associated with a cold front. Lightning associated with one of the storms killed a man who was in a boat fishing on Canyon Ferry Reservoir.
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.
Scattered thunderstorms developed over the area associated with a cold front. Lightning associated with one of the storms killed a man who was in a boat fishing on Canyon Ferry Reservoir.
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 May 18, 1:44 PM MST, 36 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 244 PM MDT FRI MAY 18 2007 .DISCUSSION... TONIGHT THROUGH SUNDAY...SHOWERS AND THUNDERSTORMS DEVELOPING THIS AFTERNOON AND EVENING ARE LIKELY TO LINGER PAST MIDNIGHT TONIGHT...WITH SOME GUSTY WINDS IN THE VICINITY OF DISSIPATING STORMS. A CONTINUATION OF EXCEPTIONAL WARMTH IS EXPECTED OVERNIGHT TONIGHT...AS WELL AS TOMORROW AFTERNOON. SOMEWHAT MOIST SOUTHWESTERLY FLOW ALOFT...COMBINED WITH AN APPROACHING COLD FRONT AND EXISTING WARM TEMPERATURES ACROSS THE FORECAST AREA...WILL CONTRIBUTE TO THE POTENTIAL FOR SEVERE THUNDERSTORM DEVELOPMENT DURING SATURDAY AFTERNOON AND EVENING OVER THE NORTH CENTRAL PLAINS AND ADJACENT MOUNTAIN RANGES. OCCASIONAL SEVERE WIND GUSTS AND A THREAT OF HAIL IS ANTICIPATED DURING THIS TIME...PARTICULARLY OVER THE EASTERN PORTION OF THE FORECAST AREA. TEMPERATURES WILL BE NOTICEABLY COOLER BY EARLY SUNDAY...WITH SHOWERS LINGERING OVER THE CENTRAL AND SOUTHWEST MOUNTAINS. ZUMPFE SUNDAY NIGHT THROUGH FRIDAY...AN ACTIVE PERIOD OF WEATHER EXPECTED DURING THIS TIME. A STRONG UPPER LEVEL TROF WILL CONTINUE TO DIG SOUTHWARD INTO SOUTHERN IDAHO BY MONDAY MORNING. THIS WILL RESULT IN WIDESPREAD PRECIP OVER MUCH OF SOUTHWEST AND CENTRAL MONTANA. THUS POPS HAVE BEEN RAISED TO LIKELY IN MOST AREAS. SNOW LEVELS WILL CONTINUE TO LOWER THROUGHOUT THE DAY ON MONDAY...WITH MOST AREAS OF SOUTHWEST MONTANA SEEING SNOW BY MONDAY NIGHT. ANY SNOW ACCUMULATIONS WILL BE CONFINED TO MAINLY GRASSY AREAS IN THE VALLEYS...BUT SEVERAL INCHES ARE LIKELY IN HIGHER ELEVATIONS (ABOVE 5000 FEET). TEMPERATURES WILL GENERALLY AVERAGE BETWEEN 10 AND 15 DEGREES BELOW NORMAL. AN UNSTABLE NORTHWEST FLOW ALOFT WILL BE OVER MONTANA AT MID-WEEK WITH SHORTWAVE ENERGY MOVING OVER MY FORECAST AREA ON THURSDAY. WILL CONTINUE TO MENTION A SLIGHT CHANCE OF SHOWERS DURING THIS TIME FRAME AND EXPECT TEMPERATURES TO CLIMB BACK TO NEAR NORMAL READINGS. UPPER LEVEL RIDGING BUILDS OVER THE PACIFIC NORTHWEST FRIDAY WITH DRY AND WARMER AIR NUDGING INTO MONTANA FROM THE WEST. MPJ/BRUSDA && .AVIATION... UPDATED 1741Z. SOUTHWEST FLOW ALOFT CONTINUES OVER THE FORECAST AREA TODAY AND TONIGHT AS AN UPPER LEVEL TROUGH MOVES INLAND OVER THE PACIFIC NORTHWEST. SURFACE LOW PRESSURE SYSTEM OVER EASTERN MONTANA AND THE DAKOTAS CONTINUES TO MOVE EAST AS CANADIAN HIGH PRESSURE BUILDS SOUTHWARD INTO NORTH CENTRAL MONTANA TODAY AND TONIGHT. THIS SYSTEM THEN MOVES EAST ON SATURDAY AS ANOTHER LOW PRESSURE SYSTEM MOVES NORTHEAST FROM THE GREAT BASIN. THE AIRMASS BECOMES UNSTABLE THIS AFTERNOON AND EVENING FOR WIDELY SCATTERED TO SCATTERED SHOWERS AND THUNDERSTORMS. VFR CONDITIONS ARE EXPECTED EXCEPT FOR LOCAL MVFR IN PRECIPITATION. MPJ && .PRELIMINARY POINT TEMPS/POPS... GTF 50 76 45 67 / 10 30 20 20 CTB 47 70 42 63 / 10 30 20 10 HLN 51 78 48 67 / 10 20 20 20 BZN 46 78 43 71 / 10 20 20 30 WEY 38 72 36 66 / 20 10 20 20 DLN 47 78 44 68 / 10 10 10 30 HVR 52 77 47 71 / 10 30 40 10 LWT 50 76 45 68 / 20 30 40 20 && .TFX WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...ZUMPFE LONG TERM...MPJ/BRUSDA AVIATION...MPJ WEATHER.GOV/GREATFALLS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREAT FALLS MT 512 AM MDT FRI MAY 18 2007 MTZ009>014-044>051-054-191115- NORTHERN ROCKY MOUNTAIN FRONT-EASTERN GLACIER-HILL-CASCADE- CHOUTEAU-CENTRAL AND SOUTHERN LEWIS AND CLARK-TOOLE-LIBERTY- EASTERN PONDERA-BLAINE-SOUTHERN ROCKY MOUNTAIN FRONT- EASTERN TETON-JUDITH BASIN-FERGUS-MEAGHER- 512 AM MDT FRI MAY 18 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...TODAY AND TONIGHT A FEW THUNDERSTORMS MAY DEVELOP THIS AFTERNOON AND EVENING. THESE STORMS MAY HAVE STRONG GUSTY WINDS AND HAIL ASSOCIATED WITH THEM. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY A FEW SEVERE THUNDERSTORMS MAY DEVELOP SATURDAY AFTERNOON AND EVENING. MAIN THREAT WITH THESE STORMS WILL BE STRONG WIND GUSTS AND HAIL. A COLD STORM SYSTEM IS EXPECTED TO AFFECT CENTRAL AND SOUTHWEST MONTANA MONDAY AND TUESDAY. SNOW LEVELS ARE EXPECTED TO LOWER TO 4500 FEET WITH ACCUMULATING SNOWS POSSIBLE IN THE MOUNTAINS. SOME SNOW IS ALSO POSSIBLE IN LOWER ELEVATIONS MONDAY NIGHT...ESPECIALLY NEAR THE ROCKY MOUNTAINS. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. MTZ008-015-052-053-055-191115- BEAVERHEAD-MADISON-JEFFERSON-BROADWATER-GALLATIN- 512 AM MDT FRI MAY 18 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST MONTANA. .DAY ONE...TODAY AND TONIGHT A FEW THUNDERSTORMS MAY DEVELOP THIS AFTERNOON AND EVENING. THESE STORMS MAY HAVE STRONG GUSTY WINDS AND HAIL ASSOCIATED WITH THEM. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY A FEW SEVERE THUNDERSTORMS MAY DEVELOP SATURDAY AFTERNOON AND EVENING. MAIN THREAT WITH THESE STORMS WILL BE STRONG WIND GUSTS AND HAIL. A COLD STORM SYSTEM IS EXPECTED TO AFFECT SOUTHWEST MONTANA MONDAY AND TUESDAY. SNOW LEVELS ARE EXPECTED TO LOWER TO 5500 FEET WITH ACCUMULATING SNOWS POSSIBLE IN THE MOUNTAINS. SOME SNOW IS ALSO POSSIBLE IN LOWER ELEVATIONS MONDAY NIGHT. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE GREAT FALLS MT
158 PM MDT FRI MAY 18 2007
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0330 PM HAIL 5 N GRASS RANGE 47.10N 108.80W
05/17/2007 E1.25 INCH FERGUS MT TRAINED SPOTTER
BRIEF PERIOD OF HAIL WITH BIGGEST PIECES THE SIZE OF A
HALF DOLLAR COIN.
0910 PM TSTM WND GST 6 N BIG SANDY 48.26N 110.12W
05/17/2007 E70.00 MPH CHOUTEAU MT TRAINED SPOTTER
WIND GUSTS IN EXCESS OF 70 MPH SNAPPED LARGE LIMBS ON
TREES.
&&
EKThe Great Falls radar (KTFX), 119 km away, was scanning. The volume nearest the first event began at 21:18 UTC.
1 lightning. Local standard time, as filed.
Man fishing alone in boat on southern Canyon Ferry Resevoir, on east shore across from Silos, struck and killed by lightning around 320 pm MDT.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Lightning, Broadwater | 2007-05-18 | 50 | Male | Boating | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2007Every state in 2007This day in weather historyWarnings in Montana, May 2007
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: 22377.