Main Street Ellicott City is experiencing flooding reminiscent to July 2016.
Howard County Fire and EMS say they're on scene making water rescues.
Officials ask anyone trapped on Main Street, to seek higher ground and wait for rescuers to get you.
Authorities say hundreds of rescuers converging on the area need access and therefore are requesting people to stay out of the area.
Standing water has been reported on many roads, including Routes 29 and 100, making roadways unsafe for drivers and pedestrians.
For those trapped in a building on Main Street, officials recommend climbing to the second floor of the building and shelter in place until rescuers come for you.
Officials are asking those in a safe place to refrain from calling 911 at this time.
Heavy rain is expected to remain through at least 6:15 p.m.