Entries tagged with “Storm surge”.


While there’s much focus on storm surge risk in New Orleans as we mark the 10th anniversary of Hurricane Katrina, two new reports highlight the vulnerability of other U.S. coastal cities to storm surge flooding.

An analysis by Karen Clark & Co ranks the U.S. cities most vulnerable to storm surge flooding based on losses to residential, commercial and industrial properties from the 100 year hurricane.

The findings may surprise you.

KCC reveals that some of the cities most vulnerable to storm surge flooding have not been impacted for decades. A few have not experienced a direct hit from a major hurricane in the historical record.

Tampa/St. Petersburg, Florida is the metropolitan area most vulnerable to storm surge flooding, according to KCC, with a loss potential of $175 billion.

Four of the top cities (Tampa, Miami, Fort Myers and Sarasota) are in Florida, and the west coast of the state is more vulnerable than the east coast.

In fact, three cities—Tampa, New Orleans and New York—will likely have losses exceeding $100 billion from the 100 year event.

KCC notes that most of the flood damage potential is currently not insured, and that “private flood insurance presents a significant opportunity for insurers that have the right tools for understanding the risk.”

Meanwhile, a new report by catastrophe modeling firm RMS, took a look at six coastal cities in the U.S. to evaluate how losses from storm surge are expected to increase in the next 85 years and found that cities such as Tampa, Miami and New York face greater risk of economic loss from storm surge.

To evaluate risk, RMS compared the chance of each city sustaining at least $15 billion in economic losses from storm surge—the amount of loss that would occur if the same area of New Orleans was flooded today as was flooded in 2005.

Based on its findings, Tampa has a 1-in-80 chance of experiencing at least $15 billion storm surge losses this year, followed by Miami with a 1-in-125 chance and New York with a 1-in-200 chance.

New Orleans still faces significant risk, with a 1-in-440 chance of at least $15 billion in economic losses related to a storm surge event, RMS noted.

Looking ahead to 2100, the likelihood of those cities sustaining this level of losses rises dramatically.

By then both Tampa and Miami will have a 1-in-30 chance of experiencing at least $15 billion in economic losses related to a storm surge event, while in New York the chance increases to 1-in-45 and in New Orleans to 1-in-315.

Here’s the visual on RMS’ findings via its infographic:

katrina-10th-anniversary-campaign-infographic

 

More than 6.6 million homes on the Atlantic and Gulf coasts are at risk of hurricane-driven storm surge with a total reconstruction cost value (RCV) of nearly $1.5 trillion.

The latest annual analysis from CoreLogic finds that the Atlantic Coast has more than 3.8 million homes at risk of storm surge in 2015 with a total projected reconstruction cost value of $939 billion, while the Gulf Coast has just under 2.8 million homes at risk and nearly $549 billion in potential exposure.

Which states have the highest total number of properties at risk?

Six states—Florida, Louisiana, New York, New Jersey, Texas and Virginia—account for more than three-quarters of all at-risk homes across the United States. Florida has the highest total number of properties at various risk levels (2.5 million), followed by Louisiana (769,272), New York (464,534), New Jersey (446,148), Texas (441, 304) and Virginia (420,052).

But if you rank the states by the highest total projected reconstruction costs in 2015, the top five are: Florida ($491.1 billion), New York ($177.4 billion), Louisiana ($162.1 billion), New Jersey ($126.8 billion) and Virginia ($91.1 billion).

CoreLogic makes the point that even though Louisiana has the second highest number of homes at risk to storm surge in 2015, only one-quarter are in the extreme or very high storm surge category, due in large part to the upgrade and expansion of levees in the state in the 10 years since Hurricane Katrina.

As Dr. Tom Jeffery, senior hazard risk scientist for CoreLogic says:

The number of hurricanes each year is less important than the location of where the next hurricane will come ashore. It only takes one hurricane that pushes storm surge into a major metropolitan area for the damage to tally in the billions of dollars. With new home construction, and any amount of sea-level rise, the number of homes at risk of storm surge damage will continue to increase.”

CoreLogic’s analysis comes as the National Hurricane Center (NHC) debuts experimental storm surge watch and warning graphics for the 2015 hurricane season:

ssgraphic_imagery_neworleans_300

Storm surge is often the greatest threat to life and property in the event of a hurricane. While most coastal residents can remain in their homes and stay safe from a storm’s winds, evacuations are generally needed to keep people safe from storm surge, the NHC says.

It’s important to note that many properties located outside designated FEMA flood zones are still at risk for storm surge damage.

As CoreLogic reminds us, homeowners who live outside the FEMA flood zones frequently do not carry flood insurance, given that there is no mandate to do so, and therefore may not be aware of the potential risk storm surge poses to their properties.

Data in the full CoreLogic report can be found here.

Check out I.I.I. facts and statistics on flood insurance here.

As we approach the peak of hurricane season, catastrophe modeler RMS has warned that storm surge poses a greater risk than hurricane wind.

RMS says its updated North American hurricane model shows there is a 20 percent chance that storm surge loss will be greater than wind loss for any U.S. hurricane that makes landfall. And for the northeast coast of the U.S. the risk is even higher.

Dr. Claire Souch, vice president, model solutions at RMS says:

Our model shows there is a 20 percent chance that storm surge loss will be greater than wind loss for any U.S. hurricane that makes landfall, which rises to almost 40 percent along the northeast coast of the United States – this is a risk the market can no longer afford to ignore.”

RMS’ updated North Atlantic hurricane model suite includes the ability to fully quantify the risk from catastrophic hurricane-driven storm surge.

An earlier paper by RMS on Superstorm Sandy made the point that storm surge loss can drive more insurance loss than hurricane wind.

In the paper RMS noted that while Sandy was not even classified as a hurricane at landfall, it caused a Category 2 storm surge in New York City:

This is not the first time that storm surge has had a dominant effect. It was responsible for more than half of the total loss from 2005’s Hurricane Katrina, which was a Category 3 storm at landfall, but had a Category 5 equivalent storm surge.”

Recent analysis by CoreLogic estimates that more than 4.2 million U.S. residential properties are exposed to storm-surge risk valued at roughly $1.1 trillion, with more than $658 billion of that risk concentrated in 10 major metro areas.

According to I.I.I. facts and stats on flood insurance, Hurricane Sandy was the second costliest U.S. flood, based on National Flood Insurance Program (NFIP) payouts as of July 12, 2013.

A new report from CoreLogic underscores just how important a purchase of flood insurance may be to homeowners, especially those living in the Northeast.

The report reveals that over four million homes in the U.S. along the Atlantic and Gulf Coasts are at risk of hurricane-driven storm-surge damage, with more than $700 billion in total property exposure.

In the Atlantic coast region alone, there are around 2.2 million homes at risk, valued at more than $500 billion. Total exposure along the Gulf Coast is nearly $200 billion, with just under 1.8 million homes at risk for potential storm-surge damage.

What this means is that there are millions of homeowners living outside of FEMA designated flood zones that might still be in an area susceptible to coastal storm-surge flooding.

CoreLogic makes the point that FEMA flood zones define areas at risk for fresh-water flooding, which is an entirely different hazard than hurricane-driven storm surge.

Extensive areas along both coasts are actually vulnerable to storm surge, yet not located within designated FEMA flood zones—and therefore homeowners are not required to purchase flood insurance.”

It goes on:

Since homeowner’s insurance excludes flood losses from either fresh or salt water, homeowners who are not located in FEMA flood zones but are in high-risk surge zones have not historically considerebuying National Flood Insurance Program (NFIP) coverage for their properties.”

To illustrate its point CoreLogic compared the number of homes in surge inundation zones against those located in both surge and FEMA flood zones for each of 14 metro areas.

For example, of 463,844 total properties exposed to flood or surge inundation in the New York/Northern New Jersey/Long Island metro area, 68.1 percent are located in a surge zone, but only 1.9 percent are located in a FEMA flood zone, while 30.1 percent are located in both a flood zone and a surge zone.

Hurricane Irene in 2011 showed the level of damage that even a weak storm could cause, but CoreLogic estimates the storm surge from a Category 4 storm hitting New York City and Long Island could cause damage of nearly $168 billion.

An I.I.I. chart shows that the top 10 most costly flood events in the U.S. ranked by NFIP payouts are associated with hurricanes or tropical storms.