1 flash flood, as filed by the National Weather Service.
Every event with a place to put it; 1 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 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 Aug 4, 2:00 PM MST, 5 hours earlier.
SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 3 PM MDT SAT AUG 4 2001 THUNDERSTORMS FORMING ALONG BACK EDGE OF DRY SLOT...PER WATER VAPOR IMAGERY...A FAVORED LOCATION. IN COORD WITH SPC AND OTHER MT OFFICES...SVR TSTM WATCH ISSUED TILL 7 PM. AXIS OF S/W STILL WEST OF MT AND WILL TRAVERSE CWA BETWEEN 00-06Z. THREAT OF DEEP CONVECTION CONTINUES... NOW TILL ABOUT 01Z...THEN MAINLY SCATTERED SHOWERS TILL MIDNIGHT. BEYOND THAT...MODELS IN FAIR AGREEMENT. NEXT COUPLE OF DAYS...UPPER RIDGE BUILDS BACK INTO MT....FLOW BECOMES DRIER AND MORE WESTERLY. QUITE WARM WITH LITTLE THREAT OF PCPN. MIELKE. EXTENDED FORECAST DISCUSSION... RIDGE WILL CONTINUE WITH SOME DECREASE IN HEIGHTS BY WED. DO EXPECT A LITTLE MORE TROFFING BY LATER IN THE PERIOD...SO THIS SHOULD KEEP IT WARM THROUGH TUESDAY. WITH THE DECREASE IN HEIGHTS...TEMPS WILL COOLE INTO THE 70S AND 80S WITH SCATTERED SHOWERS/TSTMS. CCF NUMBERS GTF UU 056 087 053 090 055 014001 CTB UU 052 082 052 085 053 013001 HLN UU 055 088 055 092 055 014101 BZN UU 052 090 052 093 054 014001 WEY UU 044 082 042 085 045 015111 DLN UU 048 086 050 089 051 014001 HVR UU 062 090 057 095 057 014001 LWT UU 056 087 056 090 056 014201
The Great Falls radar (KTFX), 85 km away, was scanning. The volume nearest the first event began at 02:01 UTC.
1 flash flood. Local standard time, as filed.
Actual event location is Cave Creek at marina on northern shore of Canyon Ferry Lake (approximately 20 E of Helena)...Brief heavy rainfall onto scorched earth (from wildfire in 2000) caused flooding on roadway...Monetary damage unknown.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2001Every state in 2001This day in weather historyWarnings in Montana, August 2001
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: 5266050.