Category Archives: Flood

Typhoon Mangkhut: A Weekend of Destruction

From the small city of Baggao, Cagayan Province in the Philippines, to Hong Kong and further into China — locations across these two countries look to recover after Typhoon Mangkhut (25W). After landfall in Guam on Monday, September 10, Mangkhut — known locally as Ompong in the Philippines, made landfall again at 2 a.m. Saturday local time (18:00 UTC, Friday, September 14) near Baggao, as the equivalent of a Category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale (SSHWS).

Maximum sustained wind speeds at landfall were 133 miles per hour (214 kilometers per hour) according to the Japan Meteorological Agency (JMA). The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) reported similar results to the JMA with maximum sustained wind speeds of 134 miles per hour (215 kilometers per hour), but the Joint Typhoon Warning Center (JTWC) reported 166 miles per hour (268 kilometers per hour), equivalent to a Category 5 major hurricane on the SSHWS.

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Hurricane Florence: Rainfall up to a 1,000-year Return Period

Florence’s much anticipated landfall occurred at 11:15 UTC (7.15 a.m. local time) today, Friday, September 14, near Wrightsville Beach, North Carolina, as a Category 1 hurricane. Florence remains just within the Category 1 hurricane classification on Saffir-Simpson Hurricane Wind Scale (SSHWS); as of the 18:00 UTC National Hurricane Center (NHC) advisory today, maximum sustained winds were 75 miles per hour (120 kilometers per hour). Previous observations showed that at Cape Lookout there were sustained winds of 83 miles per hour (133 kilometers per hour) and gusts of 106 miles per hour (170 kilometers per hour). Florence is now moving slowly toward the west at near five miles per hour (7 kilometers per hour).

Over the coming 36 hours, Florence is expected to meander into northern South Carolina and then progress further inland across the western Carolinas and into the Appalachian Mountains through the early part of next week.

The expectation that surge and inland flooding, rather than wind, would be the primary hazards associated with Florence was quickly realised as the storm approached the Carolinas coastline yesterday.

Excessive rainfall and dangerous storm surge present the greatest threat over the next few days. The potential for heavy rainfall has extended to the south and west given the change in projected track over the last 48 hours. Projections of over 15 inches (380 millimeters) of rain now cover much of southern North Carolina and northeast South Carolina — much of North Carolina is expected to receive in excess of six inches (152 millimeters) of rain.

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Florence Update: September 13

Over the last 24 hours, the structure and forecast track of Hurricane Florence has evolved significantly as the storm begins to impact the Carolinas, but the material wind, storm surge and flood threat it poses to the Southeastern and Mid-Atlantic U.S. remains.

As of 1200 UTC yesterday (September 12), Florence’s wind field was large and powerful as the storm inched closer to the U.S. coast through favorable environmental conditions. According to RMS HWind analyses, which utilize more than 30 public and private observational data sources to generate objective, ground-truth-based tropical cyclone wind field analytics, maximum 1-minute sustained winds were estimated to be 124 miles per hour (199 kilometers per hour) (Figure 1 below), placing the storm squarely in the Category 3 range on the Saffir Simpson Wind Scale.

In addition, the Integrated Kinetic Energy (IKE), an indicator of tropical cyclone strength and damage potential, was estimated to be 104 Terajoules (TJ), putting it on par with historical events like Frances (2004), Gustav (2008), and Isabel (2003).

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Florence: A New Twist in the Tale

No hurricane landfall forecast is simple. But looking back at the forecast tracks for Hurricane Florence from the National Hurricane Center (NHC) and the ensemble members of the leading global forecast models a couple of days ago, what stood out was how relatively straightforward they were. Florence was anticipated to make a steady, assured progress directly towards the Carolinas, make landfall, and move directly inland.

In a somewhat remarkable turn of events that few, if any, models predicted 48 hours ago, Florence is now expected to stall over, or very near to, the Carolina coastline.

The huge shift in the forecast guidance is the anticipated result of a reduction in Florence’s steering flow due to two competing areas of high pressure. The hurricane is currently being steered across the southwestern Atlantic Ocean towards the southeastern U.S. around the southeastern periphery of a mid-level ridge centered northeast of Bermuda. As the system approaches land, it will come under increasing influence from a competing mid-level ridge that is forecast to begin building over the east-central United States later today. The net result of these competing steering flows will see Florence slow, meander, or even become stationary for possibly 48 hours before the system moves ashore.

This possibility could bring prolonged hurricane-force winds and storm surge throughout Saturday and Sunday, to coastal areas along North and South Carolina, and significant inland flooding to whole region.

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Hurricane Florence: A Rare Event

The forecasts for Hurricane Florence have been unusually consistent this far in advance of an anticipated landfall, projecting its path to cross the coast of the Carolinas at major hurricane intensity. For some perspective, if we look at the historical hurricane record since 1850, we find major hurricane landfalls are quite rare along this part of the U.S. Atlantic coastline:

RMS Reconstructed Loss values are based on wind and storm surge damage to present-day exposure, and not on trending forward historical losses

Over the past 167 years, there have been just nine major hurricanes that made landfall along the coast of North and South Carolina. So, on average we can expect one major landfall along this 490-mile stretch of coastline every eighteen and a half years. Certainly, a rare event. Only three of these storms — Hazel, Gracie, and Hugo — were Category 4 (on the Saffir-Simpson Hurricane Wind Scale) at landfall. There has never been a Category 5 landfall north of Florida.

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EXPOSURE Magazine: Essential Reading in Changing Times

The pace of change continues to accelerate across the insurance industry, whether it is from technology, regulation or market developments, and EXPOSURE magazine helps risk professionals to explore some of the key drivers of these changes.

In this latest edition available for distribution at the Monte Carlo Rendezvous and online, the lead story looks at the recent market activity from Tower Insurance in New Zealand. By adopting high-definition earthquake modeling, Tower gained the confidence to launch risk-based pricing for its customers, providing savings for the majority of policyholders, but increases for others. EXPOSURE looks at the implications of Tower’s actions and how this could affect the New Zealand insurance market.

High resolution modeling has also helped Flood Re in the U.K. to better understand how it can work towards its remit of delivering a flood insurance market based on risk-reflective pricing that is affordable to policyholders. EXPOSURE shows how innovative use of modeling could guide Flood Re when recommending investment measures to protect properties at risk of flooding.

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Protection Gap Analytics: The Role of Risk Modeling

This is the final blog in a series of four blogs examining three potential “protection gaps” and the importance of “protection gap analytics”. To read the first blog post in this series, click here.

We are not going to be able to take effective action to reduce any of these three protection gaps unless we can first learn how to consistently measure the difference between insured and total loss. Such measurement means we can know the current situation as well as set appropriate targets and monitor progress in reducing the gap. It can also help to focus investment and action.

At present, the only form of measurement is to acknowledge the difference between insured loss and the estimated total economic loss once the claims have settled, one or two years after a significant disaster.

In the same way that probabilistic catastrophe risk models were developed to enable insurers and reinsurers to look beyond the latest event loss, so the same models are now required to monitor the protection gap. This is the focus of “protection gap analytics”.

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Schrödinger’s Cat Model

Schrödinger’s cat inhabits a thought-experiment designed to reveal the paradox of quantum properties. A hypothetical cat is sealed in a windowless box, in which there is a device that will administer a lethal poison, according to whether a single atom undergoes radioactive decay. Should the atom decay the cat will be dead. If the atom survives so will the cat. Only the quantum state of the atom is completely unknowable. So, the cat — in principle at least, is half dead and half alive. The simultaneous state of being both alive and dead is called a “superposition”.

While quantum behavior is not an average insurance coverage, (at least until future quantum computer cyber cover emerges), there are situations in the world of risk modeling that come close to Schrödinger’s cat — or perhaps that should better be Schrödinger’s “Cat” (short for Catastrophe)?

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Kerala Floods: The Role of Insurance in Building a More Resilient State

In the first twenty days of August, the state of Kerala in southern India received rainfall that was 164 percent above the average. This rain built on very wet antecedent conditions, July had seen rainfall about 40 percent above average. As a result, to manage the flood waters, state authorities were forced to open 80 dams in the region, including the Idukki dam, one of the largest arch dams in Asia. Overall, this resulted in massive flooding, displacing millions of people while claiming the lives of more than 350 citizens, destroying trees and crops and severely disrupting tourism with the closure of Cochin International airport.

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Hurricane Lane: An Offshore Threat

All eyes are on Hurricane Lane as it started to make its northerly turn towards the Hawaiian Islands late yesterday (Wednesday, August 22) and at the time of writing (Thursday, August 23, 1600 UTC) Lane is heading north, some 200 miles from the Hawaiian Islands as a Category 4 major hurricane with wind speeds of 130 miles per hour (209 kilometers per hour).

If Hurricane Lane did make landfall in the state, according to CNN it would become the first major cyclone to achieve this in 26 years, since Hurricane Iniki in 1992. Landfall does not look likely though; the current best-estimate wind field forecasts from the Central Pacific Hurricane Center (CPHC) as of 1000 UTC, Thursday August 23, show that hurricane force winds are not currently expected to impact land. But there is still an outside chance; due to Lane’s forecast track, a shift in the track direction and intensity could bring hurricane force winds onto land. Based on the current CPHC wind speed probability, there is a less than 20 percent chance of hurricane force winds impacting any of the islands in Hawaii.

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