Tropical storm Cristobal headed toward the Bahamas Sunday after leaving one person missing in the Dominican Republic, US weather forecasters said.

The storm, which was upgraded from a tropical depression, had maximum sustained winds of 45 miles (75 kilometers) an hour, the National Hurricane Center in Miami said.

It predicted heavy rainfall of four to eight inches -- "with isolated amounts of 12 inches possible" -- for the Turks and Caicos islands and southeastern and central Bahamas, it said.

In the Dominican Republic, authorities said a man was swept away when he tried to cross a rain-swollen river in his van.

Flooding near rivers and in cities also damaged more than 800 homes and cut off 23 towns, the emergency center said in its latest update. Some 4,105 people went to take refuge in the homes of family and friends, it added.

A hospital in the country's east, where the rains were heaviest, also experienced flooding on the ground floor and "patients were moving to dry places," the bulletin said.