On May 27, 2018 a massive storm released nearly two months of rain, over 9.71 inches (24.7 cm) in 2 hours on the Ellicott City area, causing catastrophic flooding in the surrounding area, which swept away several roads, cars and brought more than 10 feet of rapid moving water down Main Street in Old Ellicott City. A large portion of southbound Route 29 flooded several feet and heavy rains and rapidly rising water washed away portions of several roads.
Howard County officials reported at least 30 water rescues and one missing person as a result of the storm.
According to meteorologists, the storm was "likely worse" than the 2016 Maryland flood.
The National Weather Service reported totals in excess of 10 inches (25 cm) in several areas, with Catonsville receiving the highest at 10.38 inches (26.4 cm) and Ellicott City receiving 8.40 inches (21.3 cm).
One person was reported missing after helping a woman rescue her cat at a local pet store. Active recovery efforts were underway as of May 28th.