1 thunderstorm wind, as filed by the National Weather Service.
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 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 20, 2:00 PM MST, 2 hours earlier.
SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
300 PM MDT MON MAY 20 2002
.SHORT TERM...AREA OF INSTABILITY STRETCHES ACROSS THE CWA BUT A
FAIRLY STRONG CAP HAS BEEN INHIBITING CONVECTION. WILL CONTINUE SOME
POPS AS THE CAP SHOULD DISAPPEAR LATER THIS AFTERNOON...BUT WILL NOT
INCLUDE SEVERE WORDING. THE LARGE TROF TO THE WEST IS MOVING SLOWLY
EAST AND TWO SURFACE FRONTS WILL AFFECT THE AREA DURING THE FORECAST
PERIOD. ONE WILL BE CROSSING THE ROCKIES TONIGHT. DESPITE THE AIRMASS
CHANGE DURING THE NIGHT...FRONT CROSSES ROCKIES AROUND 6Z TUE...THE
UPPER LEVEL TROF LINGERS AND KEEPS THE AREA UNSETTLED. ANOTHER
SURFACE FRONT WILL BE MOVING SOUTH ACROSS CANADIAN BORDER 24 HRS
LATER...INTO GTF AROUND 9AM WED. MAIN AREA OF COLD TEMPS CROSSES NE
MONTANA...ALTHOUGH NORTHERN CWA SHOULD SEE TEMPS BELOW FREEZING...AND
LOW TEMPS COULD ALSO SNEAK INTO CENTRAL CWA. COLD AIR MOVING OUT OF
CANADA WILL HELP CHANCE OF PRECIP...AND WILL ALSO MAKE SOME MENTION
OF SNOW...AT LEAST ABOVE 4000 FEET AND ALONG THE BORDER. ZELZER
.EXTENDED...MRF BRINGS AN UPPER LEVEL TROF THROUGH AREA ON
FRIDAY AND THEN ZONAL FLOW THROUGH SUNDAY WITH UPPER RIDGE
BUILDING IN ON MONDAY. MRF IS A LITTLE FASTER THAN ECMWF BUT TRENDS
ARE THE SAME. WILL STAY WITH LOW POPS AND A LITTLE COOLER TEMPS.
CAMP
.CCF NUMBERS
GTF WR 050/066 042/048 030 13257
WBBBB 048/040 061/040 069/043 070/043 070 74311111111
CTB WR 046/060 040/045 028 13357
WBBBB 044/035 058/040 064/040 065/040 065 74311111111
HLN WR 050/070 045/055 034 13358
WBBBB 055/042 066/043 070/045 071/045 071 54311111111
BZN WR 045/065 038/055 030 13276
WBBBB 050/036 060/038 065/038 065/038 065 54311111111
WEY WR 036/060 030/045 024 13376
WBBBB 045/028 055/030 060/033 060/033 060 54311111111
DLN WR 044/059 038/055 030 13276
WBBBB 048/036 060/038 065/038 065/038 065 54311111111
HVR WR 048/075 045/049 028 13257
WBBBB 044/042 060/043 068/043 070/043 070 74311111111
LWT WR 048/068 039/052 030 13257
WBBBB 044/040 060/042 065/042 067/042 067 74311111111
.TFX...NONEThe Great Falls radar (KTFX), 144 km away, was scanning. The volume nearest the first event began at 22:58 UTC.
1 thunderstorm wind. Local standard time, as filed.
A severe thunderstorm near Toston tore the roof off a shed. The roof traveled 75 feet, before landing on top of a vehicle.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2002Every state in 2002This day in weather historyWarnings in Montana, May 2002
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: 5290793.