Tornadoes and Hail in Montana, July 18, 2007

Name: Tornadoes and Hail in Montana, July 18, 2007
Start: 2007-07-18T17:44
End: 2007-07-18T20:58
Location: Montana

July 18, 2007 · NWS MSO · 9 events in 5 counties and zones

On July 18, an intensely strong shortwave trough moved to the northeast across Western Montana during the late afternoon and evening hours. The breaking of a strong mid level cap released copious amount of low level instability which aided in the rapid development of severe thunderstorm super cells.

Where it happened

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

The toll

Deaths: 0
Injuries: 0
Property damage: $381,000
Crop damage: None recorded
Events: 9

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.

What happened

The episode as NWS MSO wrote it up.

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 Missoula, MT wrote its last area forecast discussion before the first event at Jul 18, 1:43 PM MST, 4 hours 1 minute earlier.

Area forecast discussion, Jul 18, 1:43 PM MST, 4 hours 1 minute before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
243 PM MDT WED JUL 18 2007

...RECORD SETTING HEAT WAVE TO CONTINUE...

.DISCUSSION...THOUGH THE HEAT WAVE IS EXPECTED TO CONTINUE AT
LEAST THROUGH THE WEEKEND THE MAIN STORY THIS AFTERNOON AND
EVENING WILL BE FOR SCATTERED...WET THUNDERSTORMS. THESE ARE EXPECTED
TO DEVELOP DURING THE MID TO LATE AFTERNOON AND MOVE TO THE
NORTHEAST. MODEL WIND PROFILES SUGGEST THAT A COUPLE OF STORMS
COULD PRODUCE STRONG WIND GUSTS AND SMALL HAIL. ISOLATED
THUNDERSTORMS ARE EXPECTED TO CONTINUE INTO THE OVERNIGHT AS A
WEAK WAVE MOVES ACROSS NORTH CENTRAL IDAHO AND NW MT INTO THE
EARLY MORNING HOURS. ON THURSDAY...THE INFLUX OF DRIER AIR AND THE
MIXING DOWN OF UPPER LEVEL WINDS (TO CREATE BREEZY CONDITIONS IN
THE AFTERNOON) MAY LEAD TO CRITICAL FIRE WEATHER CONDITIONS.
THEREFORE...A SLIGHT INCREASE IN THE COVERAGE OF SMOKE ACROSS THE
AREA MAY BE OBSERVED AS THE WIND INTERACTS WITH THE WILDFIRES
THAT ARE SCATTERED ACROSS THE AREA.

FRIDAY THROUGH WEDNESDAY...SOUTHWESTERLY UPPER LEVEL FLOW WILL
CONTINUE THROUGH THE MIDDLE OF NEXT WEEK. THIS WILL BRING
UNSTABLE...BUT DRY AND CONTINUED WARM CONDITIONS TO MOST OF THE
AREA. UNSTABLE CONDITIONS ARE EXPECTED TO MIX FAIRLY STRONG MID
LEVEL WINDS TO THE SURFACE DURING THE AFTERNOON HOURS. THERE WILL
BE A MINIMAL THREAT OF THUNDERSTORMS AS WELL INTO NEXT WEEK.

&&

.AVIATION...NO SIGNIFICANT WEATHER IMPACT TO AVIATION EXPECTED...SEE
APPROPRIATE TAFS AND TWEBS.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...FIRE WEATHER WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
     EVENING FOR DEERLODGE/WEST BEAVERHEAD-EAST BEAVERHEAD-EAST
     LOLO.

ID...NONE.
&&

SHORT TERM...HENRY
LONG TERM....STEGEMILLER
AVIATION...DICKERSON

Hazardous weather outlook, Jul 18, 8:52 AM MST, 8 hours 52 minutes before

HAZARDOUS WEATHER OUTLOOK...CORRECTION
NATIONAL WEATHER SERVICE MISSOULA MT
952 AM MDT WED JUL 18 2007

IDZ005>010-MTZ001>007-043-191100-
NORTHERN CLEARWATER MOUNTAINS-SOUTHERN CLEARWATER MOUNTAINS-
OROFINO/GRANGEVILLE REGION-LOWER HELLS CANYON/SALMON RIVER REGION-
WESTERN LEMHI COUNTY-EASTERN LEMHI COUNTY-KOOTENAI/CABINET REGION-
WEST GLACIER REGION-FLATHEAD/MISSION VALLEYS-
LOWER CLARK FORK REGION-MISSOULA/BITTERROOT VALLEYS-
BITTERROOT/SAPPHIRE MOUNTAINS-BUTTE/BLACKFOOT REGION-
POTOMAC/SEELEY LAKE REGION-
952 AM MDT WED JUL 18 2007 /852 AM PDT WED JUL 18 2007/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL
IDAHO...NORTHWEST MONTANA AND WEST CENTRAL MONTANA.

.DAY ONE...TODAY AND TONIGHT

SCATTERED STRONG THUNDERSTORMS WILL DEVELOP ACROSS PORTIONS OF
WESTERN AND NORTHWESTERN MONTANA THIS AFTERNOON...PERSISTING INTO
THE LATE EVENING HOURS. GUSTY WINDS AND SMALL HAIL WILL BE
POSSIBLE WITH ANY STORM THAT DEVELOPS. A COUPLE OF THESE STORMS
COULD BECOME SEVERE. HEAVY RAIN WILL BE POSSIBLE WITH SOME STORMS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

TEMPERATURES WILL REMAIN WELL ABOVE NORMAL. BREEZY WINDS IN THE
AFTERNOON MAY CREATE AREAS OF SMOKE THROUGH THE PERIOD ESPECIALLY
OVER THE CAMAS PRAIRIE AND OTHER VALLEY LOCATIONS.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

In the hours before

Local storm report, Jul 18, 1:38 PM MST, 4 hours 6 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
238 PM MDT WED JUL 18 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0824 AM     TSTM WND DMG     DIXON                   47.32N 114.31W
07/17/2007                   SANDERS            MT   PUBLIC

            FENCES...POWER POLES AND LARGE SPRUCE TREES WITH 2.5 FOOT
            DIAMETER TRUNKS BROKEN AND/OR BLOWN OVER.

&&

DICKERSON

Local storm report, Jul 18, 2:21 PM MST, 3 hours 23 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
321 PM MDT WED JUL 18 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0800 PM     TSTM WND DMG     RAVALLI                 47.28N 114.18W
07/17/2007                   LAKE               MT   NWS EMPLOYEE

            REPORT OF ONE LARGE TREE BLOWN DOWN...SEVERAL LARGE
            BRANCHES BROKEN AND IN ROAD.

&&

DICKERSON

Local storm report, Jul 18, 2:23 PM MST, 3 hours 21 minutes before

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE MISSOULA MT
323 PM MDT WED JUL 18 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0800 PM     TSTM WND DMG     RAVALLI                 47.28N 114.18W
07/17/2007                   LAKE               MT   NWS EMPLOYEE

            REPORT OF ONE LARGE TREE BLOWN DOWN...SEVERAL LARGE
            BRANCHES BROKEN AND IN ROAD.

&&

DICKERSON

The radar

The Missoula radar (KMSX), 58 km away, was scanning. The volume nearest the first event began at 00:44 UTC.

Open the radar archive at this moment

Event by event

4 thunderstorm wind, 3 hail, 2 tornado. Local standard time, as filed.

Hail, Mineral

When: July 18, 5:44 PM MST
Where: Mineral County, Tarkio
Measured: 1.75 in hail
Reported by: Broadcast Media
Coordinates: 47.020, -114.750

Golf ball size hail was reported to KECI TV Meteorologist from a weather spotter in Tarkio.

Hail, Sanders

When: July 18, 6:30 PM MST
Where: Sanders County, Perma
Measured: 0.88 in hail
Reported by: Emergency Manager
Coordinates: 47.370, -114.600

Emergency Management reported nickel size hail in Perma.

Tornado, Lake

When: July 18, 6:50 PM MST to 7:40 PM MST
Where: Lake County, 10 mi WNW of Pablo to 8 mi ENE of Rollins
Rating: EF0
Path length: 1 mi
Path width: 50 yd
Property damage: $8,000
Reported by: Public
Coordinates: 47.655, -114.318

The public reported a tornado 10 miles west northwest of Pablo and also a waterspout over Flathead Lake north of Polson. In addition, a sail boat (located on the Flathead County/Lake County line) was spun around at least once in a counterclockwise direction and then sank.

Thunderstorm Wind, Lake

When: July 18, 6:55 PM MST to 7:25 PM MST
Where: Lake County, 3.73 mi WNW of Pablo to 0.43 mi N of Polson
Measured: 78 kt (90 mph) estimated gust
Property damage: $30,000
Reported by: NWS Storm Survey
Coordinates: 47.615, -114.197

National Weather Service storm survey crew saw numerous trees and several power poles down along the storm's track. Two structures received roof damage. The damage observed was indicative of straight line winds. A flag pole was bent in half southwest of Polson. Based upon the damage observed, winds were estimated to be between 80 to 100 mph.

Thunderstorm Wind, Lincoln

When: July 18, 7:20 PM MST to 7:35 PM MST
Where: Lincoln County, Libby
Measured: 61 kt (70 mph) estimated gust
Property damage: $35,000
Reported by: Trained Spotter
Coordinates: 48.380, -115.530

Estimated thunderstorm wind gusts to 70 mph produced substantial structural damage to the drive-in theater and the town ball park. Numerous large trees were also blown down.

Thunderstorm Wind, Flathead

When: July 18, 7:25 PM MST to 7:55 PM MST
Where: Flathead County, 0.95 mi WNW of Lakeside to 0.79 mi NW of Kalispell City Arpt
Measured: 78 kt (90 mph) estimated gust
Property damage: $300,000
Reported by: NWS Storm Survey
Coordinates: 48.028, -114.237

Numerous trees and power poles were blown down along the northern shores of Flathead lake. The roof to Carpenter's Arena near Kalispell was blown off. Damage to two other roofs was observed. One small grain silo was blown over near Somers. The damage observed from the NWS storm survey crew was indicative of straight line wind damage. Based upon the damage observed, winds were estimated to be between 80 and 100 mph.

Tornado, Flathead

When: July 18, 7:40 PM MST to 8:30 PM MST
Where: Flathead County, 8 mi SSW of Bigfork to Bigfork
Rating: EF0
Path length: 8 mi
Path width: 50 yd
Property damage: $8,000
Reported by: Public
Coordinates: 47.963, -114.136

The public reported a waterspout on Flathead lake along the Flathead/Lake County line. A sailboat at this location was spun around at least once in a counterclockwise direction and then sank.

Hail, Flathead

When: July 18, 8:35 PM MST
Where: Flathead County, 0.3 mi ESE of Kalispell
Measured: 0.88 in hail
Reported by: Amateur Radio
Coordinates: 48.199, -114.314

Nickel size hail was reported covering the ground in Kalispell. Power was also reported out to most of the county.

Thunderstorm Wind, Sanders

When: July 18, 8:50 PM MST to 8:58 PM MST
Where: Sanders County, Lone Pine
Measured: 61 kt (70 mph) estimated gust
Reported by: Public
Coordinates: 47.700, -114.630

Several large trees blown down. Windows blown out on mobile homes from straight line winds.

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
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.
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.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Montana in 2007 Every state in 2007 This day in weather history The tornado archive for Montana, 2007 Warnings in Montana, July 2007

Sources

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: 47108, 47113, 47112, 77906, 47114, 77905, 47111, 47115, 47116.