Name: Hail and Damaging Wind in Montana, August 6, 2004
Start: 2004-08-06T20:45
End: 2004-08-06T21:15
Location: Montana

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

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The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 2

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.

Strong thunderstorms moved through Sanders and Lake Counties during the evening hours producing heavy rain, hail, damaging winds and igniting several lightning strike fires. Thunderstorm winds blew down trees over Highway 35 around Flathead Lake and down the Mission Valley. Trees were blown down onto power lines. which triggered some small fires near Arlee.

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 Aug 6, 7:25 PM MST, 1 hour 20 minutes earlier.

Area forecast discussion, Aug 6, 7:25 PM MST, 1 hour 20 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
825 PM MDT FRI AUG 6 2004

.UPDATE...NO UPDATE TO ZONES OR STATE AT THIS TIME. MSX RADAR
INDICATED WIDESPREAD SHOWERS AND THUNDERSTORMS MOVING ACROSS
EASTERN WASHINGTON INTO THE IDAHO PANHANDLE. AS THE TROUGH CONTINUES
TO MOVE TO THE EAST THESE SHOWERS WILL SPREAD ACROSS THE FORECAST
AREA...WITH THE BEST CHANCE OF GETTING SOME RAIN FALL NORTH OF
MISSOULA. THIS COVERED WELL IN CURRENT FORECAST...TEMPERATURES LOOK
TO BE ON TRACK.

&&
.PREVIOUS DISCUSSION...TONIGHT...WIDESPREAD SHOWERS AND THUNDERSTORMS
CURRENTLY OVER WASHINGTON AND OREGON UNDER A VIGOROUS MOIST PACIFIC
TROUGH.  IN ADDITION...A STRONG...ALMOST FALL LIKE...JET STREAK IS
MOVING UNDER THE BASE OF THIS TROUGH ENHANCING CONVECTION AS THE
NOSE OF THE JET MOVES EAST. THIS SYSTEM WILL MOVE OVER WEST CENTRAL
IDAHO AND NORTHWEST MONTANA OVERNIGHT.  TEMPTED TO GO 100 PERCENT
CHANCE OF PRECIPITATION NORTH TONIGHT...BUT DECIDED NOTHING IN
WEATHER PREDICTION IS ABSOLUTELY CERTAIN...SO BACKED OFF TO
WIDESPREAD 70 PERCENT CHANCES. SOUTHWEST MONTANA AND EAST CENTRAL
IDAHO WILL SEE SCATTERED TO ISOLATED SHOWERS AND THUNDERSTORMS AS
BULK OF DYNAMICS MOVE ACROSS THE NORTH.

SATURDAY...PRECIPITATION WILL DECREASE THROUGH THE DAY AND BE
ISOLATED MAINLY NEAR GLACIER PARK BY AFTERNOON AS SYSTEM MOVES EAST.
MAIN WEATHER FEATURE WILL BE STRONG WESTERLY WINDS...PARTICULARLY IN
HIGHER TERRAIN AS WESTERLY SURFACE GRADIENT SETS UP BEHIND THE FRONT
AND UPPER LEVEL WINDS MIX TO THE SURFACE...PARTICULARLY ALONG THE
CONTINENTAL DIVIDE.

SATURDAY EVENING THROUGH THURSDAY...VERY LITTLE CHANGE TO THE
PREVIOUS FORECAST.  A HIGH PRESSURE RIDGE IS STILL EXPECTED TO BUILD
IN SUNDAY BEHIND THE STRONG UPPER LEVEL LOW. THIS RIDGE WILL PERSIST
THROUGH THE LONGTERM PERIOD...BRINGING DRY WEATHER TO MUCH OF THE
NORTHWEST AND NORTHWEST FLOW INTO CENTRAL IDAHO AND NORTHWESTERN
MONTANA. THE MODELS SEEM TO BE IN BETTER AGREEMENT THAT THE RIDGE
AXIS WILL STAY TO THE WEST OF OUR REGION. A RESPECTABLE SURFACE
GRADIENT ALSO BUILDS ON MONDAY AND TUESDAY BETWEEN THE HIGH PRESSURE
TO THE EAST AND THE THERMAL TROUGH TO THE WEST. TEMPERATURES WILL BE
AT OR ABOVE NORMAL BY MID-WEEK. &&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
ID...NONE.
&&

UPDATE/KOLATA
PREVIOUS DISCUSSION/MWJ/KREYENHAGEN

Hazardous weather outlook, Aug 6, 12:35 PM MST, 8 hours 10 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MISSOULA MT
135 PM MDT (1235 PM PDT) FRI AUG 6 2004

IDZ009-010-MTZ006-007-070330-
WESTERN LEMHI COUNTY-EASTERN LEMHI COUNTY-
BITTERROOT/SAPPHIRE MOUNTAINS-BUTTE/PINTLAR REGION-
135 PM MDT FRI AUG 6 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL IDAHO AND WESTERN
MONTANA

.DAY ONE... TODAY

ISOLATED STRONG THUNDERSTORMS ARE POSSIBLE OVER THE SOUTHERN
BITTERROOT AND SAPPHIRE MOUNTAINS...THE BUTTE AND PINTLAR
REGION OF MONTANA AND LEMHI COUNTY OF IDAHO THIS AFTERNOON AND EARLY
EVENING AS A UPPER LEVEL WEATHER DISTURBANCE PASSES THE AREA. THE
MAIN THREAT FROM STORMS TODAY WILL BE STRONG GUSTY WINDS.

.DAYS TWO THROUGH SEVEN... SATURDAY THROUGH THURSDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

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

The radar

The Missoula radar (KMSX), 51 km away, was scanning. The volume nearest the first event began at 03:44 UTC.

Open the radar archive at this moment

Event by event

1 hail, 1 thunderstorm wind. Local standard time, as filed.

Hail, Sanders

When: August 6, 8:45 PM MST
Where: Sanders County, 10 mi W of Dixon
Measured: 0.75 in hail
Reported by: GENERAL PUBLIC
Coordinates: 47.317, -114.533

Thunderstorm Wind, Lake

When: August 6, 9:15 PM MST
Where: Lake County, 12 mi N of Polson
Measured: 53 kt (61 mph) estimated gust
Reported by: EMERGENCY MANAGER
Coordinates: 47.850, -114.167

What these are

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

More

Every storm in Montana in 2004 Every state in 2004 This day in weather history Warnings in Montana, August 2004

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: 5420026, 5420027.