May 9, 2018
Multiple thunderstorms developed over north-central and southwest Montana during the afternoon and evening of May 9th, 2018 as a shortwave trough and accompanying Pacific cold front approached from the west. An ordinary cell thunderstorm produced a brief tornado six-miles southwest of Moore, MT in the early evening. Multiple pictures indicated the tornado lofted dirt into the air, but no damage, injuries, or deaths occurred. Also, a flash flood occurred in Helena later that evening.
Source: NOAA National Weather Service Storm Events Database (event 745706). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Lewis And Clark County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.