Seven of every eight homes in Terrebonne and Lafourche parishes, a combined 70,738 homes valued at almost $14 billion, are at risk of being damaged by hurricane storm surges, according to a new report release last week by CoreLogic.
CoreLogic, a global property research company, issued a report Thursday that examines risk from hurricane-driven storm surge for homes along the U.S. Atlantic and Gulf coastlines across 19 states and the District of Columbia, as well as 86 metro areas.
The release of the annual report coincided with the start of hurricane season June 1, and shows that nearly 6.9 million homes along the coasts are at a potential risk.
Of the combined 70,738 homes in the Lafourche-Terrebonne area:
- 30,008 are designated to be in the “extreme” storm surge risk zone, meaning that they would be affected by all hurricane category levels in a direct hit, the study says.
- Another 31,975 homes are listed as high risk, susceptible to flooding from Category 2 or higher hurricanes.
- Another 8,747 homes, are listed as high risk, susceptible to flooding from a Category 3 or higher hurricane.
- Eight houses are at moderate risk, from a Category 4 or 5 storm.
Home replacement values in the report are based on 100 percent damage to the structure. Depending on the amount of surge water from a given storm, there may be less than 100 percent damage to the residence, which would result in a lower figure.
Terrebonne has 45,000 housing units, Lafourche 40,000, according to 2016 figures from the U.S. Census Bureau. Of those 85,000 homes, the CoreLogic report says 83 percent are at risk of damage or destruction from a hurricane storm surge.
A storm surge is a massive rise in water that sweeps onto shore at the same speed as a hurricane, usually around 10-15 mph. The destructive and often-deadly surge can stretch miles long and push miles inland.
The highest on record was 27.8 feet above mean seal level, recorded at Pass Christian, Miss., during Hurricane Katrina in 2005, according to Weather Underground.
The highest high-water mark -- a combination of normal tides, storm surge and waves on top -- was also recorded for Katrina. In Biloxi, Miss., a high-water mark of 34.1 feet above mean sea level was recorded on the outside of the Beau Rivage Lighthouse. The surge was 22 feet high in Biloxi, so the combination of the tide, about 1 foot, and 11-foot waves on top of the storm surge created the 34.1-foot high-water mark.
States with less coastal exposure but lower-lying elevations that extend farther inland, such as Louisiana, tend to have more total homes at risk because of the potential for surge water to travel farther inland.
Louisiana ranks second both for the total number of at-risk homes, 808,000, and total estimated replacement cost, $181 billion.
New Orleans ranks fourth among metro areas with the most homes at risk from storm surge, 391,004. Lafayette ranks 15th with 122,196 homes at risk. At the top of the list are Miami, New York and Tampa.
Federal forecasters predicted last week that this season will produce an average to above-average number of hurricanes.
The National Oceanic and Atmospheric Administration (NOAA) predicted the 2017 hurricane season will see 12 total storms, six of which will develop into hurricanes, and three of those are predicted to be Category 3 or higher.
"Despite the fact that this year's hurricane season is predicted to have fewer storms than last year, it doesn't mitigate the risk of storm surge damage," said Dr. Tom Jeffery, senior hazard scientist at CoreLogic. "As we've seen with past storms, even one single hurricane at a lower-level category can cause significant damage if it makes landfall in a highly populated area."
Posted on Tue, June 6, 2017
by The Lafourche Gazette