"It's flooding in quite a bit of places," Adam said, citing reports from Pearlington, Lakeshore and parts of Waveland and Bay St. Louis.
Police waved drivers off U.S. 90, the main beach road in Gulfport, because of flooding. A billboard had torn loose and water stood foot-deep in some areas, knee-deep elsewhere.
Adam said crews successfully rescued three people who had called for help after a houseboat broke loose in Pearlington, near the Louisiana state line but had no major incidents to report immediately.
Hancock County is unusually vulnerable to storm surge because water driven into the Mississippi Sound piles up against the V-shape coast where Louisiana and Mississippi come together. Adam said he wasn't sure if any structures had been damaged. Most buildings destroyed by 2005's Hurricane Katrina in Hancock County were elevated when rebuilt.
American Red Cross spokesman Jay Huffstatler said nearly 2,000 people had entered a total of 33 shelters in Mississippi.
"We've had a great turnout at shelters, people are taking the storm seriously," Huffstatler said.
In Jackson County, Monica Cooper, a spokeswoman for the emergency management agency, was currently reporting 80 flooded roads and reports were increasing "steadily."
She said low lying areas of Moss Point, Gautier and St. Martin were among the hardest hit with flooding. She said the flooding was a combination of heavy rainfall and storm surge.
Cooper said she could not confirm reports that some homes had flooded.