How Much Rain is Too Much?

How much rain has fallen in the past few days?

The Tiber and Patapsco Rivers swelled in Ellicott City Wednesday, leading to flooding along the Historic District’s Main Street, a voluntary evacuation of businesses and water damage to storefronts and vehicles.

But the rain started days earlier, with a forecast that warned of precipitation in the coming week. On Monday the BWI weather station recorded 1.43 inches of rain, according to NWS. 

On Tuesday, that same station recorded 1.84 inches of rain.

Things took a turn toward the torrential on Wednesday, when the BWI weather station recorded 3.4 inches of rain. It was a lot of precipitation, but not enough to break the record for this day of the month: 3.84 inches, on Sept. 7, 1934.

And on Sept. 24, 1912, the area saw 5.97 inches of rain in one day.

The Patapsco receded late Wednesday afternoon; roads were re-opened and so were a few businesses.

As of just after 9 a.m. on Thursday, NWS reported that streams were beginning to lower, but that scattered, moderate rain showers were still moving through the area. 

“Streams are beginning to recede … but remain extremely high … and the ongoing rain will likely slow the fall of the high water,” the forecast discussion reads.

A flash flood warning remains in effect until 4 p.m. Thursday.