Rapid attribution of the extreme rainfall in Texas from Tropical Storm Imelda

The study finds that the extreme two-day rainfall during Tropical Storm Imelda in September 2019 was made more likely and more intense by anthropogenic climate change. Observational data suggests the probability of such an event has increased by a factor of 2.6 since 1900, while climate model synthesis indicates a probability increase of 1.5 to 3.1 times and an intensity increase of 9% to 21%. The report also notes that rapid urban expansion and loss of impervious cover in Southeast Texas have exacerbated flooding risks for approximately 6.6 million people in the impacted counties.

• The two-day precipitation recorded on 19–20 September 2019 during Tropical Storm Imelda was extreme, with a local return time of approximately 1200 years at the station with the highest rainfall total. However, the regional return time for such an event occurring at any of 85 stations along the U.S. Gulf Coast is lower, at about 1 in 50 years.
• Statistical analysis of observations indicates that the probability of such extreme rainfall has increased by a factor of 2.6 (range 1.6 to 5.0) since 1900, which corresponds to an 18% (range 11% to 28%) increase in rainfall intensity for such an event.
• High-resolution climate models (EC-Earth 2.3 and HiFLOR) suggest that anthropogenic climate change has made two-day extreme precipitation events as intense as those seen during Imelda 1.6 to 2.6 times more likely, or 9% to 17% more intense.
• A synthesis of both observational and model data concludes that the probability of two-day rainfall as intense as the maximum observed during Imelda increased by a factor of 1.5 to 3.1, representing an intensity increase of 9% to 21%.
• Climate change, combined with sea level rise and rapid urban expansion characterized by a loss of impervious cover, has led to more frequent and intense flooding in coastal Southeast Texas, where an estimated 6.6 million people live in the counties impacted by Imelda.
• Following Hurricane Harvey, Texas implemented several risk-reduction measures, including a hazard disclosure law, the creation of the Flood Infrastructure Fund (nearly $1.7 billion) and the Texas Infrastructure Resiliency Fund ($1.6 billion), and the development of a statewide flood plan via SB8.

APA

World Weather Attribution (2019). Rapid attribution of the extreme rainfall in Texas from Tropical Storm Imelda. https://www.worldweatherattribution.org/rapid-attribution-of-the-extreme-rainfall-in-texas-from-tropical-storm-imelda/

Chicago

World Weather Attribution. Rapid attribution of the extreme rainfall in Texas from Tropical Storm Imelda. 2019. https://www.worldweatherattribution.org/rapid-attribution-of-the-extreme-rainfall-in-texas-from-tropical-storm-imelda/.

Wikipedia

{{cite report |author=World Weather Attribution |title=Rapid attribution of the extreme rainfall in Texas from Tropical Storm Imelda |date=27 September 2019 |url=https://www.worldweatherattribution.org/rapid-attribution-of-the-extreme-rainfall-in-texas-from-tropical-storm-imelda/ |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{worldweatherattribution2019rapid, author = {{World Weather Attribution}}, title = {{Rapid attribution of the extreme rainfall in Texas from Tropical Storm Imelda}}, institution = {World Weather Attribution}, year = {2019}, month = sep, url = {https://www.worldweatherattribution.org/rapid-attribution-of-the-extreme-rainfall-in-texas-from-tropical-storm-imelda/}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }