In pictures: 40,000 homes flooded in Louisiana

The death toll from historic flooding in Louisiana climbed to 11 on Tuesday as the expanding flood zone prompted authorities to declare disasters in 20 parishes of the southeastern US state.

Here is a selection of images to illustrate the impact of the floods . . .

A person is seen on the front porch of a home as it is surrounded by flood waters in Port Vincent, Louisiana.

Flooded areas of Baton Rouge, Louisiana, are seen from the air.  As many as 20,000 people have been rescued following unprecedented floods in the southern US state of Louisiana, including a 78-year-old woman who spent a night stranded in a tree, police said late Monday. (AFP/US Coast Guard).

Residents awoke to find their homes and businesses still surrounded by muddy water, and vehicles submerged, without clear answers about when the epic flooding is expected to recede.

These people gathered their belongings after evacuating on August 16, 2016 in Gonzales.

A family of deer make their way through flood waters in Gonzales, Louisiana. While flooding receded in parts of southern Louisiana, other areas saw rising waters. The National Weather Service issued renewed flood warnings.

Alan Johns gives Chanvuthea Keo a ride in his canoe as he makes his way home through flooded streets in Denham Springs.

Twenty parishes -- similar to counties in other states -- were declared emergency disaster areas, up from four on Monday and 12 earlier on Tuesday. Ann Chapman from the Louisiana State Animal Response Team is pictured here carrying a dog she helped rescue from flood waters in Baton Rouge.

 Rescue crews were searching for more victims, with officials uncertain about how many people remain missing. Here, a Coast Guard crew searches by helicopter for people who may need assistance in flooded areas of Baton Rouge. (AFP/US Coast Guard).

 A sign is seen along a flooded road on August 15, 2016 in Baton Rouge. Record-breaking rains pelted Louisiana over the weekend, leaving the city with historic levels of flooding that have caused at least 11 deaths and damaged thousands of homes.

This image from video provided by the Louisiana Army and Air National Guard shows residents being evacuated from floodwaters in Baton Rouge.