During and after Allison's landfall extremely heavy rainfall occurred over much of eastern and southeastern Texas, and much of southwestern Louisiana. Several locations on the east side of Houston received more than 30 inches of rainfall. A total of 23 tornadoes were confirmed from Mississippi to South Carolina from 11-16 June Specifically, 10 tornadoes were reported in South Carolina, 4 in Mississippi, 3 in Florida, 2 in both Alabama and Georgia, and 1 each in Louisiana and Virginia. The   damage estimates reported by the Federal Emergency Management Agency (FEMA) and other state emergency management agencies were near $5 billion, with approximately $4.8 billion in the Houston metropolitan area alone. More than 14,000 homes were destroyed or received major damage, and nearly an additional 34,000 homes incurred at least minor damage.

Forty-one deaths are directly related to the heavy rain, flooding, tornadoes, and high surf generated by Tropical Storm Allison and its remnant subtropical circulation. The death toll by state is as follows: Texas 23, Florida 8, Pennsylvania 7, Louisiana 1, Mississippi 1, and Virginia 1. Twenty-seven of these deaths were due to drowning in freshwater flooding.  These damage and direct death toll estimates make Allison the deadliest and most costly tropical or subtropical storm on record in the United States.