Twenty years after Allison hit Houston, it’s still the costliest tropical storm in history

Several cars trapped on 6-10 at I-10 during tropical storm Allison

HOUSTON – While the Gulf Coast has been hammered by big hurricanes in recent years, the system that hit the Houston-area 20 years ago this week remains the costliest tropical storm in history. Allison never rose to hurricane status, but its impact went into the record books.

The storm began as a tropical wave off Africa on May 21, 2001. Within five days, it had traveled west and over northern South America before continuing west across Central America and into the eastern Pacific on June 1. By June 4, it had moved into the Bay of Campeche and toward Galveston where, by the afternoon of June 5, it officially became Tropical Storm Allison.

As the storm moved inland and quickly lost wind strength and tropical storm status, heavy rainfall records were set within the five days the storm lingered in Southeast Texas. The storm moved north across Houston on June 6, and the next day, Allison stalled near Lufkin as a depression. It took a southwesterly turn on June 8 and by June 9, things began to get even more difficult.

  • Scroll down to view KPRC archive news clips from 2001.
  • Share your memories of Tropical Storm Allison in the comments section below.

Allison’s slow and erratic progress moving inland and back out to the Gulf set it apart from every storm to hit Texas in the past century.

An analysis was later done on the path of Allison as it became a storm to remember. It was the first tropical storm ever to have its name retired, alongside hurricanes like Katrina, Rita, Ike, and Harvey.

Two million people were affected. Most of the deaths occurred from people walking or drowning in high water.

The National Weather Service issued a Flash Flood Warning three hours before the first fatality, and five hours before the first drowning.

When Allison was finally finished, 41 people were killed across the country, 95,000 cars were flooded and 73,000 homes were damaged. More than 30,000 people were left stranded in shelters. Greens Bayou saw 27 inches of rain and other places experienced even more flooding.

The storm also destroyed 25 years of research at the Texas Medical Center.

Locally, 18 people drowned and three people were electrocuted. Death and destruction were everywhere.

Allison was dropping more than five inches of rain an hour. Incredibly, the storm had more life, and from June 9 to June 17, it traveled east/northeast through eight more states, killing dozens and causing millions more in damages.

Tropical Storm Allison’s damage estimate with today’s adjusted costs is just shy of $13 billion, making it one of the top twenty most costly tropical cyclones in U.S. history according to a report from the NOAA’s National Centers for Environmental Information and the National Hurricane Center.


Houston highways underwater in 2001
Houston highways were under water during tropical storm Allison 20 years ago
Excerpt of KPRC 2 meteorologist Khambrel Marshall’s reporting in 2001
Winds came in at 60mph during Tropical Storm Allison
Flooding devastated the Texas Medical Center in 2001
Memorial Hermann hospital flooded during Tropical Storm Allison
Excerpt of reports from Galveston in 2001

About the Authors:

KPRC 2's chief meteorologist with three decades of experience forecasting Houston's weather.

Journalist, meteorologist, community leader and volunteer.