(January 9, 2012)--Thunderstorms in the Houston prompted tornado warnings Monday morning and knocked out electricity to nearly 20,000 homes and businesses while in Central Texas, authorities were keeping a close eye on low-lying areas as heavy rain fell.

The Mall of the Mainland in Texas City was evacuated because of a possible tornado, which caused roof and wall damage.

The mall was closed until a structural engineer investigated the stability of the building.

Floodwaters trapped students at two Houston elementary schools Monday afternoon after an intersection flooded.

Emergency crews brought in boats to get the students out and to a nearby YMCA where parents were waiting.

Killeen firefighters rescued a man who was canoeing Monday morning in Nolan Creek.

Deputy Fire Chief Kenneth Hawthorne said the man was pulled from the creek at around 10 a.m. Monday in the area of Lowes Boulevard between Trimmier and W.S. Young after running into difficulties in the swift-moving water.

He was treated at the scene for minor injuries.

Killeen officials planned to keep a close eye on the creek and other flood-prone areas as rain continued to fall Monday.

In Central Texas, rain chances stand at near 100 percent Monday and isolated thunderstorms are possible.

Rain chances continue Monday night and into Tuesday.

(Rachel Cox contributed to this story)