Erin dropped up to 10 inches of rain in parts of San Antonio and Houston, and officials throughout central and southern Texas braced for the possibility of more rain Friday morning while also keeping an eye on Dean as it ripped through the Caribbean with 100 mph winds, ripping off roofs in the French island of Martinique.
Overnight rain prompted the evacuation early Friday of three areas in Texas' Bandera County, officials said.
While there were no serious injuries in that area, a man was swept away Thursday in San Antonio after apparently getting out of his vehicle in floodwater, a police spokeswoman said. Three people died in a head-on collision on a rainy highway in Comal County, but Department of Public Safety Trooper Rick Alvarez said the cause of the crash was still under investigation.
In Houston, two people died after the waterlogged roof of a storage unit outside a Houston grocery store collapsed, according to Houston fire and Harris County hospital officials. Also in Harris County, a truck driver drowned in when his truck went into a flooded retention pond, according to county's Office of Emergency Management.
Summer storms have poured record rainfall across Texas and parts of Oklahoma and Kansas, with floods killing 22 people since mid-June.
The dangers of a slow-moving storm system are well known in Houston, where Tropical Storm Allison stalled for several days in 2001, soaking the flat, low-lying city. After passing Houston, it returned, dumping about 20 inches of rain in eight hours. About two dozen people died, most of the city was without power and entire neighborhoods were destroyed.
Still, state and local officials said Erin was a relatively calm rehearsal for the hurricane season.
In the Atlantic, Dean was centered about 50 miles west-southwest of Martinique at 8 a.m. EDT, and moving west at about 23 mph. The Category 2 hurricane was expected to intensify as it entered the warm waters of the Caribbean, heading toward Jamaica.
It was too early to tell whether the storm would eventually strike the United States, but officials were gearing up for the possibility of the season's most severe storm yet.
"It's really moving fast, and the forecast track keeps it at that speed," said meteorologist David Paul of CBS affiliate KHOU in Houston. "We could end up being threatened by this hurricane.
"Because of that, take this weekend to get your preparations in order," Paul said.
Shell Oil Co. evacuated 188 people this week from offshore facilities in Erin's path and said Thursday that it was monitoring Dean.