Author Archives: Jeff Waters

About Jeff Waters

Meteorologist and Manager, Model Product Strategy, RMS
Jeff Waters is a meteorologist who specializes in tropical meteorology, climatology, and general atmospheric science. At RMS, Jeff is responsible for guiding the insurance market’s understanding and usage of RMS models including the North American hurricane, severe convective storm, earthquake, winter storm, and terrorism models. In his role he assists the development of RMS model release communications and strategies, and regularly interacts with rating agencies and regulators around RMS model releases, updates, and general model best practices. Jeff is a member of the American Meteorological Society, the International Society of Catastrophe Managers, and the U.S. Reinsurance Under 40s Group, and has co-authored articles for the Journal of Climate. Jeff holds a BS in geography and meteorology from Ohio University and an MS in meteorology from Penn State University. His academic achievements have been recognized by the National Oceanic and Atmospheric Administration (NOAA) and the American Meteorological Society.

The Next Sandy

As we have seen with recent events such as Hurricane Katrina, Hurricane Ike, and most recently Superstorm Sandy, coastal flood damage can be disproportionately large compared to wind damage.

See the recent RMS infographic on hurricanes, which highlights the risk of storm surge.

Following the flooding in Manhattan and along the New Jersey shores, Sandy highlighted the need for comprehensive, high-resolution coastal flood modeling solutions. Sandy also provided deeper insights into flood coverage terms and assumptions across various lines of business throughout the insurance industry.

With the anniversary of Superstorm Sandy (October 29) approaching, RMS identified which coastal cities may be hit with a major coastal flood event.

Closed subway station in Lower Manhattan, NY, after Hurricane Sandy hit in 2012

Using RiskLink 13.0, the latest version of our North Atlantic Hurricane model suite, RMS calculated the 100-year return period (RP) surge loss contribution (%) for 12 coastal central business districts, which ranged from Galveston to New York City.

Baltimore and Biloxi are at highest risk, driven by 100-year RP surge contributions of 61% and 51%, respectively, across all lines of business.

Believe it or not, cities like Miami and the Outer Banks in North Carolina exhibited some of the lowest risk against a major surge event, with 100-year RP contributions of 5% each.

Consistent across all high-risk cities:

  • Located in fairly low-lying areas at or below sea level
  • Close to shallow-sloping sea beds

These characteristics, among others like wind intensity and angle of landfall, effectively allow for surge to gradually build throughout an approaching storm and impact nearby coastal regions with little or no resistance.

Storm surge damage

Storm surge damage to a residential structure in Toms River, NJ, as a result of Sandy

In RiskLink 13.0, the RMS view of coastal flood risk remains up-to-date. With the core hazard modeling methodology in place since 2011, RMS has integrated the latest science, data, and industry development into the high-resolution (as high as 180 meters along coastlines and within regions of high exposure densities), hydrodynamic storm surge model from DHI known as MIKE 21.

The inclusion of these updates effectively reduces the uncertainty associated with surge hazard and loss, and ensures that the RMS coastal flood model continues to be the only credible model for quantifying surge risk accurately.

The market has taken notice. In July 2013, RMS was selected by First Mutual Transportation Authority to model the risk for the first ever storm surge catastrophe bond.

With these advancements and over 30,000 stochastic events that impact the U.S. comes a deeper insight into when and where the next major coastal flood event could occur. For instance, Superstorm Sandy surge losses contributed to 65% of total insured losses.

In RiskLink 13.0, there are over 3,000 stochastic events that do the same, which translates to an annual likelihood of about 10% across all U.S. hurricane states, based on long-term hurricane frequencies. This annual likelihood nearly triples in the Northeast (29%) and doubles in the Gulf (17%), the two regions at highest risk of experiencing the next Sandy-like event.

Similarly, given that a hurricane impacts the U.S., there is a 30% annual chance that the full insured surge loss will exceed $1 billion USD, and nearly a 14% chance that the same losses exceed $5 billion USD.

Regardless of when or where the next major surge event occurs the industry needs to have the right tools available in order to model the magnitude and severity of catastrophic storm surge accurately. For instance, coastal flood models such as MIKE 21 simulate surge characteristics throughout the lifetime of the event, not just at landfall, because it is well known that hurricanes with similar landfalling characteristics do not always produce the same surge risk.

Equally as important is the need for coastal flood models like MIKE 21 to be able to capture the localized nature of key geographical and geological features such as topography, land use, land cover, and bathymetry.

As the industry continues to gain a better understanding of their coastal flood risk landscape, especially on the local scale, RMS will continue to help by incorporating the latest available data and research into our model, investigating the underlying uncertainties and modeling challenges, and investing in future modeling capabilities on RMS(one).

The 2013 Atlantic Hurricane Season: Historically Quiet or Just Getting Started?

It’s no secret. Despite consistent forecasts of another above average season and an uptick in activity over the last few days, the 2013 Atlantic Hurricane season got off to a historically quiet start. Of the nine named storms that have formed thus far, only two have reached hurricane strength (Humberto on September 11 and Ingrid on September 15). It is the first season in 11 years without a recorded hurricane by the end of August, and only the second season since 1944 where a hurricane had not formed by the climatological peak of hurricane season (September 10).

Number of tropical cyclones that form per 100 years in the Atlantic Basin

Number of tropical cyclones that form per 100 years in the Atlantic Basin

Part of the reason behind the slow start is the large amount of dry Saharan air pushing sand and dust into the atmosphere off of the west coast of Africa, effectively stabilizing the atmosphere and disrupting tropical waves from developing off the African coast. Also, strong wind-shear in the upper atmosphere and cooler-than average sea-surface temperatures (SSTs) in the eastern Atlantic have combined to suppress tropical cyclone development and intensification even further.

Some scientists are suggesting that this is the beginning of a bigger trend in hurricane activity given the changing climate, where warmer atmospheric conditions may act to reduce the likelihood of hurricane landfalls along the Atlantic Coast due to stronger atmospheric winds blowing west to east during hurricane season, effectively pushing storms away from the U.S.

Such findings are consistent with RMS’ new Medium-Term Rates (MTR) forecast, which was released earlier this year as part of the Version 13.0 North Atlantic Hurricane Model suite. Informed by an original study that involved simulating over 20 million years of hurricane activity under various SST regimes, we found that the proportion of land falling hurricanes decreases as SSTs increase.

Despite the relatively calm beginning, there is no indication that the second half of the season would resemble the first half.

As a comparison, the 1988 season didn’t produce a storm of hurricane strength until September 2, but eventually went on to produce Hurricane Gilbert, a Category 5 event in Mexico and the Caribbean that caused more than $7 billion USD in economic damage as the most powerful Atlantic hurricane on record until Hurricane Wilma in 2005.

Similarly, the first hurricane of the 2001 season, Hurricane Erin, formed on September 9, yet that season ended with 15 named storms including 9 hurricanes, 4 of which reached major hurricane status.

This chart below shows the tracks of all tropical cyclones in the 2012 Atlantic hurricane season. The points denote the location of each storm at 6-hour intervals, while the colors and symbols signify the storm’s intensity and corresponding category at each interval, respectively.

Hurricane tracks for the 2012 Atlantic Hurricane season

Hurricane tracks for the 2012 Atlantic Hurricane season

Climatologically, September is the busiest month for tropical cyclones in the Atlantic, producing an average of 3.5 named storms annually, 2.4 of which become hurricanes. In fact, of the 280 hurricanes that made landfall in the U.S. since 1851, over one-third of them (104) occurred in September.

It is at this time of the year when the tropical conditions are most conducive for tropical cyclone formation and development: Atlantic SSTs are at their warmest (generally in excess 26°C or 80°F), the tropical atmosphere is unstable and favorable for convection (i.e. thunderstorms), vertical wind shear is low, and there is usually a peak in frequency of rotating, low-level disturbances moving off of Africa across the tropics, which are the systems that eventually become tropical cyclones.

This month marks the notable anniversaries of several historic September hurricanes.

  • The 1903 Vagabond Hurricane celebrates its 110th anniversary on September 16, being the most recent hurricane to make first landfall in the state of New Jersey
  • Shortly thereafter on September 18 is the 10th anniversary of Hurricane Isabel, one of the top 5 costliest Mid-Atlantic hurricanes of all time
  • After that, September 21 marks the 75th anniversary of the 1938 New England Hurricane, the most intense and deadliest hurricane in New England history
  • Toward the end of the month is the 15th anniversary of Hurricane Georges on September 25, which made landfall in at least 7 different countries including the U.S. and at the time, was the costliest hurricane since Hurricane Andrew (1992)

With nearly half of the season to go, the 2013 Atlantic hurricane season may end up being one of the quietest seasons on record. However, as we have seen in years past, it also may be just getting started.

120 Years Since the 1893 NY Hurricane & the Disappearance of Hog Island

As the industry and modeling organizations continue to learn from the impacts of Hurricane Sandy in 2012, it’s important to know that this event, although historical and record breaking on many counts, was not unprecedented.

The historical record shows that there have been dozens of other tropical cyclones to impact the Northeast U.S., some of which were more intense than Hurricane Sandy from both a wind and surge perspective.

Noteworthy examples include the 1938 New England Hurricane, 1954 Hurricane Carol, and the 1893 New York Hurricane, which will be marking its 120th anniversary on August 24. This storm is notable for being one of only two hurricanes to make a direct landfall in New York City, the other being the 1821 Long Island Hurricane.

First identified as a tropical storm on August 15, 1893 in the central Atlantic Ocean, the storm gradually intensified over the next seven days as it tracked northwestward toward the U.S. By August 22, it had reached its peak intensity of 115 mph (185 km/h), categorizing it as major hurricane status (Category 3). At this point, it began to recurve to the north, bringing it in-line with coastal New Jersey and New York. Two days later, after land interaction with parts of New Jersey resulted in some weakening, the storm made landfall on western Long Island with peak winds around 85 mph (140 km/h).

The hurricane impacted much of the coastal and interior portions of the Northeast with tropical-storm force winds, and much of the New York City with hurricane-force winds. From a surge perspective, the storm brought a 30-foot (9.1 m) storm surge that completely flooded southern Brooklyn and Queens, NY, along with many other low-lying regions.

Here is an extract from the New York Times on August 25, 1893.

Given the severity of this storm’s surge component, it is well known for destroying the majority of Hog Island, a 1 mile (1.6 km) long island that existed south of the modern-day Long Island coast.

According to version 13.0 of the RMS U.S. Hurricane Model, if the 1893 New York Hurricane were to occur today, the modeled insured losses from a wind-only perspective would be $6.4 billion, and $6.9 billion from a wind and surge perspective. Although not as damaging as Hurricane Sandy, this storm would be a top-10 historical event in the Mid-Atlantic and Northeast regions.

Compared to Hurricane Sandy, the 1893 New York Hurricane was estimated to have been smaller in overall size and intensity at landfall, but significantly larger in terms of surge height and extent. Model-generated hazard and damage footprints for the 1893 New York Hurricane are narrower in width and comparable in terms of peak wind gust.

Further, the impacted areas are confined to coastal New England regions due to the traditional clockwise recurving nature of the storm. On the contrary, Hurricane Sandy took a counterclockwise turn toward the coast just before landfall and prior to recurving toward the north and east, which resulted in a hazard footprint that included many Mid-Atlantic states.

Nevertheless, an event such as the 1893 New York Hurricane demonstrates that from a hazard perspective, Hurricane Sandy was not an once-in-a-lifetime type of storm.

Similar events have and will continue to occur in the future, especially given the period of heightened hurricane activity in the Atlantic, and high surge risk in the Northeast U.S. During this time, it is imperative that the industry increases awareness of these risks and monitors them accordingly.