Aon Benfield Analytics | Impact Forecasting Hurricane Maria Event Recap Report March 2018 Risk. Reinsurance. Human Resources. Aon Benfield Analytics | Impact Forecasting Table of Contents Executive Summary 3 Meteorological Recap 4 Event Details 11 Lesser Antilles 11 Greater Antilles 14 Energy Impacts 20 Transportation Impacts 22 Environmental Impacts 24 Historical Comparison 25 Impact Forecasting Reconnaissance Trip 26 Impact Forecasting: Modeled Results 29 Financial Losses 30 Appendix A 31 Appendix B 32 Appendix C 33 Appendix D 34 Contact Information 37 Hurricane Maria 2 Aon Benfield Analytics | Impact Forecasting Executive Summary Hurricane Maria became the costliest hurricane to track across the Caribbean on record, and the second- costliest storm of the 2017 Atlantic Hurricane Season. The powerful system left catastrophic damage and human impact on the island of Puerto Rico and elsewhere in the Caribbean, including Dominica and the U.S. Virgin Islands. Extended power outages and destroyed infrastructure in Puerto Rico led to significant business interruption. The total economic cost of Maria was roughly estimated around USD65 billion. Public and private insurers cited payouts around USD27 billion. Maria was officially recognized as a Tropical Storm by the National Hurricane Center on September 16, 2017. The storm tracked through an area with extremely warm ocean waters and low wind shear, reaching Category 1 intensity by September 18. In a span of only 24 hours, Maria underwent an extremely rapid intensification cycle to reach Category 5 intensity, which was shortly followed by a direct landfall on the island of Dominica with devastating effects. In the following hours and days, Maria tracked closely to the areas previously affected by Hurricane Irma. Despite undergoing an eyewall replacement cycle, the storm did not weaken during the regeneration process and reach its peak intensity with sustained winds of 175 mph (280 kph). In the morning hours of September 20, Maria made landfall in southeastern Puerto Rico as a Category 4 hurricane after undergoing an eyewall replacement cycle. This made Maria the strongest storm to come ashore on the island since 1928. It would become the costliest disaster in the history of Puerto Rico. After exiting the island, Maria took a turn to the north and did not directly affect the mainland United States. However, some impacts resulting from high surf was felt in several coastal Atlantic states. A combination of extreme wind speeds, dangerous storm surge and torrential rainfall resulted in substantial damage on several Caribbean islands. Hurricane Maria was the first Category 5 storm on record to make landfall in Dominica, a small Caribbean nation. Extreme conditions resulted in damage or destruction of 98 percent of buildings on the island. Widespread damage in all sectors of the economy occurred and more than 30 people lost their lives. Impacts of lesser degree were also felt on the neighboring islands of Martinique and Guadeloupe. Widespread damage was sustained by the U.S. and the British Virgin Islands, which were previously affected by Hurricane Irma. Maria’s impact in Puerto Rico was devastating and resulted in the worst natural catastrophe to ever impact the island. Official statistics estimated that at least 55 people had died and a minimum of 250,000 homes had been severely damaged or destroyed across the island. The catastrophe also highlighted the issue of a significant portion of residential property being built illegally. A majority of residents did not own hazard insurance and the vast majority of the insured loss in Puerto Rico was sustained by the commercial sector. Prolonged power and water outages impacted the entire island months after the catastrophe and led to major business interruption. Apart from widespread wind damage, coastal and inland flooding ensued and rivers crested at record levels. Hurricane Maria became one of the costliest natural catastrophes ever recorded globally. It became the eighth-costliest event in terms of economic loss, and sixth from the insurance perspective. Together with Hurricanes Harvey and Irma, Maria substantially contributed to a high economic toll during the 2017 Atlantic Hurricane Season. Total economic losses are estimated at USD65 billion, with the insurance sector covering USD27 billion. The vast majority of the Maria’s impact was recorded in Puerto Rico. Hurricane Maria 3 Aon Benfield Analytics | Impact Forecasting Meteorological Recap The National Hurricane Center (NHC) began watching an organizing cluster of thunderstorms on September 14 (00:00 UTC) after it had exited the west coast of Africa a few days prior. The agency initially gave the tropical wave a 30 percent chance of developing into a tropical cyclone during the next five days. However, the system began to organize more quickly than initially thought and the NHC declared the system Potential Tropical Cyclone Fifteen on September 16 (15:00 UTC). During this time, initial tropical storm watches were issued for parts of the Leeward Islands. (Beginning in 2017, the NHC started using the term ‘Potential Tropical Cyclone’ to describe a disturbance that is not yet a tropical cyclone, but poses the threat of bringing tropical storm or hurricane conditions to land areas within 48 hours.) The NHC would officially deem the disturbance a Tropical Depression on September 16 (18:00 UTC) and Tropical Storm Maria just three hours later. The storm continued to get better organized while tracking west-northwestward through the Tropical Atlantic Ocean. Steady intensification occurred as Maria moved through an area with minimal vertical wind shear and extremely warm ocean waters. The cyclone would officially reach hurricane intensity with 75 mph (120 kph) winds on September 17 (21:00 UTC) while the outer fringes of the system started to enter the Leeward Islands. Maria’s explosive 24-hour intensification (Source: NASA, CSU) Hurricane Maria 4 Aon Benfield Analytics | Impact Forecasting By September 18, Maria was a Category 1 hurricane with 80 mph (130 kph) sustained winds. During the next 24 hours, it would undergo explosive rapid intensification to Category 5 intensity. During the 24 hour span between September 18 (00:00 UTC) and September 19 (00:00 UTC), the NHC projected that Maria would undergo intensification with a likelihood of becoming a major hurricane (Category 3 or greater) during the next 24 hours. One of the more trusted statistically-based intensity models – known as the SHIPS Rapid Intensification Index – gave a 51 percent chance of rapid intensification by 30 knots during the upcoming 24 hour timeframe. Maria would eventually intensify by 70 knots in the 24 hour stretch and reaching an incredible intensity of 160 mph (260 kph) while nearing the island of Dominica. The minimum central pressure would fall from 982 millibars to 925 hours during this time as well; further signifying Maria’s explosive growth. Maria landfall in Dominica (Source: Meteo France) Maria would officially make landfall in Dominica at approximately 9:15 PM local time on September 18 (01:35 UTC September 19) as a Category 5 hurricane with 160 mph (260 kph) winds. This is the first time on record that a Category 5 storm has made landfall in Dominica. After landfall, Maria continued to track west-northwestward with slight wobbles as the system initially started to show signs of an eyewall replacement cycle. This was significant given that the storm had a small hurricane wind field, with hurricane-force winds only extending roughly 30 miles (45 kilometers) from the center. Given the small wind radii, this meant that any slight wobble could have a major impact in terms of wind-driven damage across the rest of the Caribbean. Hurricane warnings were in effect for much of the northern Caribbean – including the U.S. Virgin Islands, the British Virgin Islands, Puerto Rico, and other small islands in the Lesser Antilles – on September 19 as Maria moved closer to impacting areas only recently devastated by Hurricane Irma. After moving away from Dominica, Maria briefly weakened below Category 5 intensity with 155 mph (250 kph) winds, but would regain Category 5 strength in less than four hours while traversing very warm waters in the Caribbean. During the day on September 19, Maria continued to track west-northwestward towards the Virgin Islands (British and U.S.) and Puerto Rico. The system maintained Category 5 strength with 160 mph (260 kph) winds as large swells began to batter many islands. An eyewall replacement cycle did commence as the hurricane and tropical storm-force wind field radii began to expand. However, similarly to Hurricane Irma, Maria did not weaken during the regeneration process. In fact, pressure levels continued to drop and wind speeds slightly increased during the day. The new peak intensity was 175 mph (280 kph) as minimum central pressure plunged to 909 millibars. Maria’s eyewall passing USVI, September 20 (Source: NOAA) Hurricane Maria 5 Aon Benfield Analytics | Impact Forecasting Maria officially made landfall in Puerto Rico at around 06:15 AM AST on September 20 (10:15 UTC) as the center of its circulation crossed the southeastern shores of the island near Yabucoa, located approximately 30 miles (48 kilometers) SSE of San Juan. Maria made landfall as an extremely dangerous Category 4 storm with 155 mph (250 kph) sustained winds, shortly after being downgraded from the highest category. This was the strongest landfall in Puerto Rico since 1928 and the first Category 4 storm to directly affect the island Maria at Puerto Rico landfall, thermal satellite image (Source: NASA, CSU) since 1932. The center of Maria’s circulation exited Puerto Rico at around 02:00 PM AST (06:00 UTC). After spending roughly four hours over land, it emerged in the Atlantic as a weakened Category 3 strength hurricane with sustained wind speeds of 115 mph (185 kph). Maria continued to bring torrential rainfall to Puerto Rico as it tracked towards the Dominican Republic that prompted extensive flash flooding.