Flash Flood in Yellowstone County, Montana

Flood waters from a thunderstorm turned downtown streets into rivers, parking lots into lakes and basements into swamps. So much rain fell so fast on Billings that storm drains wide enough to hold a small car were filled for hours. Streets turned into rushing rivers, basements filled with muddy water and some residents went swimming with shovels and sticks to clear clogged storm drains. More than an inch of water seeped into the Billings Clinic hospital corridors and the basement near the buildings north entrances. Mud and water flooded the atrium area of Billings Clinic. In the hospital's north parking lot, storm water rose above the tires of passenger cars. Flooding was also reported in the underground parking garage of the hospital. Flash flooding was also reported on Alkali Creek as the creek flooded in several places. There were numerous calls of flooding in the basements of residential homes and businesses and water being over roads in some places. In addition, manhole covers were blown off by the pressure of water flooding the city's storm sewer system. The heavy rain caused a significant amount of water damage throughout the main part of the city.

Meteorologically speaking, this was a very active severe weather day for south central Montana. A very moist and unstable atmosphere was in place across portions of the Billings Forecast area during the afternoon and evening of the 20th (Father's Day). A moist, southeast surface flow, strong wind shear aloft, and ample afternoon heating provided the necessary ingredients for severe weather. Numerous thunderstorms, some of which became rapidly severe producing tornadoes and large hail, developed across South Central Montana.