What is in this dataset?
This table lists nine major flood events in Greater Houston, from 1935 to 2019. Each row gives the dates, a rainfall figure with its time span and location, the number of structures flooded and the fatalities reported, with the source for each.
| event | dates | rainfall_inches | rainfall_measure | rainfall_location | structures_flooded | fatalities | source |
|---|---|---|---|---|---|---|---|
| December 1935 flood | December 1935 | https://www.hcfcd.org/portals/62/about/flooding-history/historytimeline-24x36-1.pdf | |||||
| Tropical Storm Claudette | July 1979 | 43 | 24-hour total | Alvin | https://www.hcfcd.org/portals/62/about/flooding-history/historytimeline-24x36-1.pdf | ||
| Tropical Storm Allison | June 5-9, 2001 | 37 | Five-day total (nearly 37 inches) | Port of Houston | More than 70,000 (Harris County) | 22 | https://webarchive.library.unt.edu/eot2008/20090509120926/http://www.srh.noaa.gov/hgx/projects/allison01.htm ; https://www.hcfcd.org/portals/62/about/flooding-history/historytimeline-24x36-1.pdf |
| Hurricane Ike | September 2008 | 2,500 by storm surge and 1,200 more by rainfall | 11 (Harris County) | https://www.hcfcd.org/portals/62/about/flooding-history/historytimeline-24x36-1.pdf | |||
| Memorial Day Flood 2015 | May 25-27, 2015 | 11 | Three-hour total (nearly 11 inches) | Brays Bayou | More than 6,000 | 7 | https://www.hcfcd.org/portals/62/about/flooding-history/historytimeline-24x36-1.pdf |
| Tax Day Flood | April 17-18, 2016 | 13-17 | 12-hour total | Upper Cypress Creek, Addicks and Barker watersheds | About 9,820 (Harris County, estimated) | 7 | https://hcfcd.org/storm-center/spring-floods-2016 ; https://www.hcfcd.org/portals/62/about/flooding-history/historytimeline-24x36-1.pdf |
| Memorial Day Flood 2016 | May 2016 | 8-13 | Storm total | North Harris County | More than 400 in Harris County and more than 900 in the Spring Creek watershed in Montgomery County | https://www.hcfcd.org/portals/62/about/flooding-history/historytimeline-24x36-1.pdf ; https://hcfcd.org/storm-center/spring-floods-2016 | |
| Hurricane Harvey | August 25-29, 2017 | 26-47 | Storm total range across Harris County | Harris County | 154,170 homes (Harris County) | 36 (Harris County) | https://communityimpact.com/news/2018/06/08/hurricane-harvey-damage-report-harris-county ; https://www.weather.gov/hgx/hurricanes_climatology_2010s |
| Tropical Storm Imelda | September 17-19, 2019 | More than 30 | Three-day total | Southeast Montgomery, northeast Harris and Chambers counties | https://www.weather.gov/hgx/hurricanes_climatology_2010s |
Download the full dataset (CSV)
How were events chosen?
Events come from the Harris County Flood Control District’s flooding history timeline and its storm pages, and from National Weather Service storm summaries. Each event is one for which these agencies report flooded structures, extreme rainfall or deaths in the region. The list is not complete. Many smaller floods are on the district’s timeline but not here.
How was the data compiled?
- Rainfall figures are copied as the agency states them, with the time span: 3 hours, 12 hours, 24 hours or a storm total.
- Where an agency gives a range, the range is kept.
- Structure counts and deaths are for Harris County unless the row says otherwise.
- Blank cells mean no figure was found in the sources used.
What do the figures show?
Community Impact reported that Hurricane Harvey flooded 154,170 homes in Harris County, more than any other event in the table. Between 26 and 47 inches of rain fell across the county from August 25 to 29, 2017. The National Weather Service office in the Houston area recorded 43.38 inches. The U.S. Geological Survey reported new peaks of record at 40 of 74 USGS streamgages in its Harvey study.
Tropical Storm Allison dropped nearly 37 inches at the Port of Houston from June 5 to 9, 2001. The Flood Control District counts more than 70,000 flooded structures and 22 deaths.
Tropical Storm Claudette produced a U.S. record of 43 inches of rain in 24 hours at Alvin in July 1979, according to the district’s timeline.
What are the limits?
- Rainfall figures use different time spans and are not directly comparable.
- The 1935 flood has no rainfall or damage figure in the sources used. The timeline records Buffalo Bayou at 52 feet above normal.
- The timeline gives Hurricane Ike’s flooding as 2,500 structures from storm surge and 1,200 from rainfall. It gives no rainfall total.
- The Flood Control District gives May 26-27 on its timeline and May 27-28 on its storm page for the 2016 Memorial Day flood, so the table shows May 2016. Its storm page also gives both April 16-17 and April 17-18 for the Tax Day Flood. The table uses April 17-18, the dates on the timeline.
- Harvey figures for Harris County are from news coverage of the county’s final damage report. The report itself was not opened for this release.
See the Harris County Flood Control District and Harris County.