By Verna Gates
BIRMINGHAM, Alabama (Reuters) - A storm moving across the U.S. Gulf Coast battered parts of Alabama and Florida with up to 18 inches of rain on Saturday with authorities in Pensacola, Florida, declaring a state of emergency and sending out boats to rescue residents of flooded homes.
The heavy rains in the region began on Friday night. The storm is due to winds picking up tropical moisture and streaming it from New Orleans in the Gulf Coast to Jacksonville on Florida's eastern coast.
Mobile, Alabama, saw 15 inches of rain that stranded people in cars and caused a dam to break on a private lake, officials said.
Pensacola and Mobile, which are less than 60 miles apart, have been the worst-hit areas, said Mike Pigott, senior meteorologist with private firm Accuweather.com. Those have "kind of been two bull's eyes to be honest with you," he said.
The two cities are along the Gulf Coast's Interstate-10 corridor, which has seen the most severe rain and flooding.
In Escambia County, which includes Pensacola and is on the border with Alabama, officials declared a state of emergency and advised residents in low-lying areas to evacuate.
A massive surge of floodwater at a Pensacola apartment complex stranded many first-floor tenants, and about 100 people had to be rescued, said Jacob Conner, volunteer communications commander for Escambia County Search and Rescue.
"We came in with two rescue boats the size of fishing boats," Conner said. "We ran a three-hour rescue operation. We were rescuing families, children, babies and elderly residents."
Two emergency shelters opened in Escambia County for displaced residents, said county communications coordinator Cam Johnson. "We estimate that a couple of hundred people are flooded out," Johnson said.
In Alabama between Dawes and Saint Elmo, which are within 10 miles of each other and southwest of Mobile, there were reports of more than 18 inches of rain on Saturday, Accuweather.com said on its site.
Pensacola had more than 13 inches of rain on Saturday, and Mobile had a record amount of rainfall for a 24-hour period with more than 15 inches, said Jason Beaman, meteorologist for the National Weather Service in south Alabama.
"It's wet, way too wet," Beaman said.
The only time Pensacola saw more rainfall was on a day in 1934 when 15.29 inches fell, he said.
"Mobile has seen tremendous flooding," Beaman said. "People have had to be rescued from vehicles, businesses and homes. Some of the people in cars either underestimated the depth of the water, or it came up on them fast."
On a 14-acre private lake in the Mobile area, a dam broke due to rising waters and people were stranded in their homes, Beaman said.
The storm is expected to continue for 24 hours to 36 hours and move into northern Alabama and Georgia, Pigott said.
(Writing by Alex Dobuzinskis; Editing by Bill Trott)