Most Hurricane Harvey deaths happened outside flood zones

New research suggests Hurricane Harvey was deadlier outside the 100- and 500-year floodplains drawn by the federal government.

"It was surprising to me that so many fatalities occurred outside the flood zones," Sebastiaan Jonkman, a professor of hydraulic engineering at Delft University of Technology in the Netherlands, said in a news release.

At least 88 deaths have been blamed on Harvey. Some 80 percent were caused by drowning. Surprisingly, just 22 percent of the 37 deaths recorded in Houston's Harris County -- the epicenter of the disaster -- occurred inside the 100-year flood zone.

The 100- and 500-year flood zones define the probability of the land within the contour lines being flooded. A neighborhood within the 100-year zone can be expected to flood once a century. The odds of flooding within the 500-year zone are smaller -- a 0.2 percent probability of flooding during any given year. Hurricane Harvey was larger than a 500-year flood, affecting land outside the flood zones.

Unprecedented rainfall totals lasting more than a week triggered flooding across an area of southeast Texas roughly the size of the Netherlands.

Researchers at Delft and Houston's Rice University began analyzing fatalities within days of the storm. They found 19 of the deaths in Harris County occurred outside the flood zones.

"The number of fatalities outside of the floodplains highlights how widespread flooding from Harvey really was," Jonkman said.

Scientists found that most of the drowning deaths occurred in cars or when people trapped in cars tried to get out and were swept away. The second leading cause of death, after drowning, was electrocution by downed power lines. Several deaths were also blamed on an inability of medical personnel to reach those in need of treatment.

Researchers published their analysis of Harvey deaths in the journal Natural Hazards and Earth System Sciences.

The authors of the study say flood maps are still useful. However, researchers believe zoning efforts should be improved and officials should identify high-risk areas outside of the 100- and 500-year floodplains.

"Better communication of their purpose and limitations would help reduce risk," said Jonkman.

Related Links
Bringing Order To A World Of Disasters
When the Earth Quakes
A world of storm and tempest

Tweet

Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Monthly Supporter
$5+ Billed Monthly

paypal only

SpaceDaily Contributor
$5 Billed Once

credit card or paypal

Hundreds take shelter as Fiji braces for another cyclone
Wellington (AFP) April 7, 2018
Hundreds of people were sheltering in evacuation centres as another tropical storm took aim at Fiji, officials said Saturday, as the South Pacific island nation went on high alert. The storm was brewing east of Vanuatu and was expected to strengthen as it neared Fiji early next week. "The concern for the weekend is strong winds, heavy rain, flooding of low lying areas and rivers," the Fiji Meteorological Service said in a statement. It comes a week after Cyclone Josie caused widespread flood ... read more