Tropical Storm Allison was a tropical storm that devastated southeast Texas.

The tropical storm came over the city of Houston, Texas in June 2001. Nobody expected it to cause damage, but the storm lingered. Its rain caused the Brays Bayou, the Buffalo Bayou, and the Sims Bayou to burst its banks.

21 people died in the flooding in Houston. It left people homeless as their homes were rebuilt or remodeled. Many middle-class were forced to stay in apartments or at a relative's house until their houses were free of mold and other complications brought on by the flooding.

Several hospitals at the Texas Medical Center had to evacuate their patients after flood waters disabled the power generators in the basement, causing the power to go out. Also, lab animals that were part of crucial experiments drowned at the Baylor College of Medicine.

In Downtown Houston, the underground tunnel got swamped, and a woman drowned in an elevator in the Bank of America Center.

Tropical Storm Allison eventually left Houston and passed over the southeastern United States. It would cause more flooding in Pennsylvania before it dissipated off of the North Atlantic Ocean.