He said emergency workers were "making every effort to locate that individual".
Water rushes through Main Street in Ellicott City, Md., on Sunday.
Howard County police identified him as 39-year-old Eddison Hermond of Severn. He said some of the areas repaired after the 2016 devastation withstood Sunday's flood waters.
Kittleman said he considers the damage worse than the flooding two summers ago. Many had just finished recovering and rebuilding from the previous disaster in 2016.
"It's significantly higher than it was before", she told the newspaper, comparing the floodwaters to those of 2016.
"This is an extremely unsafe and potentially catastrophic situation", the NWS said, adding that at least five roads in Baltimore have been shut down due to flooding.
"There are a lot of people whose lives are going to be devastated again, and they've been working so hard to come back", Kittleman said.
Local media reported up to 8 inches of rain had fallen on Ellicott City in only two hours. Some spots may have received 10 inches of rain in a three-hour span.
Koh Lanta 2018 : Clémence, gagnante du combat des héros face à Pascal
Après une courte réflexion, il choisit doit choisir celui qu'il affrontera lors du dernier Conseil, et il désigne Clémence . Pour plusieurs d'entre eux, le candidat a mené une belle aventure et aurait mérité la place de vainqueur.
The flash floods that began on Sunday flooded buildings and destroyed vehicles.
The rain propelled the muddy flood water down through Ellicott City. No fatalities or missing people were reported. Others said they gathered in the second story of a building and anxiously watched the seething waters.
Some business owners aren't sure if they can rebuild again, especially since officials have said this flood was worse then the last one.
Officials also told stories of heroism - including one of a Howard County police officer who nearly lost his life trying to help a family evacuate. But the Maryland city around 13 miles west of Baltimore was hit Sunday by flooding that was even worse than 2016.
One person is missing after a flash flood in Ellicott City, Maryland, Sunday.
Some are already asking whether enough was done after the last flood to prevent a similar catastrophe.
Hogan said he is heading to the scene. And you saw, we get the money from FEMA two years later.
As flash flooding rips through Maryland, knocking down cars and soaking the ground floors of buildings, locals trapped by the deluge have been posting videos and photos of the calamity.