Baton Rouge — Thousands of people in southern Louisiana hunkered down in shelters on Monday, forced out of their homes by intense flooding that took many people by surprise.At least six people were killed. The weather had improved from the torrential downpours that began on Friday but rivers and creeks in many areas were still way above flood stage, and people downstream eyed the deluge with concern.Rescuers evacuated more than 20 000 people since the flooding started and more than 10 000 people were in shelters.In high-water vehicles, boats and helicopters, emergency crews hurried to rescue scores of people and the governor warned it was not over.From the air, homes looked more like little islands surrounded by flooded fields. Farmland was covered, streets descended into impassable pools of water, shopping centres were inundated with only roofs of cars peeking above the water.From the ground it was just as catastrophic.Abandoned cars were pushed to the side of the road, lawn furniture and children's toys floating through the waters."The rivers and streams north of Interstate 12 have crested and have started to drop, while those south of the interstate continue to rise," meteorologist Mike Efferson said. He said the Baton Rouge area could see up to a half-inch of rain on Monday.The federal government declared a major disaster, specifically in the parishes of Tangipahoa, St. Helena, East Baton Rouge and Livingston. More parishes could be added as assessments are done, and officials are advising residents to document all their damage.Six people have died, Devin George, the state registrar for vital records, said on Monday.The evacuees included the governor and his family, who were forced to leave the Governor's Mansion when chest-high water filled the basement and electricity was shut off.