Hurricanes of 2018 – a Tale of Two Landfalls

Aon Benfield invited IBHS to contribute perspectives on significant weather events during 2018 for the Weather, Climate & Catastrophe Insight: 2018 Annual Report developed by Impact Forecasting, a wholly owned subsidiary of Aon. We were proud to offer guidance and insights on both wildfire and this piece on hurricanes.

 

As devastating forces of nature, 2018’s Hurricane Florence in coastal North Carolina and Hurricane Michael in the Florida Panhandle left loss and harm in their wake. They also taught important lessons that can improve our defense against future storms and enhance forecasting prowess.

Florence had an unprecedented landfalling track, which complicated forecasting. Just prior to landfall, Florence slowed and her winds weakened, but the wide storm pushed an enormous surge on shore and lingered to dump heavy inland rainfall. The result was historic flooding across the entire region and serious wind damage along the immediate coast.

While the nation watched Florence approach for days, it seemed that Michael emerged “out of nowhere.” Michael formed near the Yucatan Peninsula and raced across the Gulf of Mexico, strengthening rapidly just before landfall. Michael was a rare event with winds at landfall that exceeded the design level for the area. The damage in Mexico Beach and Panama City illustrates how catastrophic a Category 4 hurricane can be.

Both storms brought punishing wind, wind-driven rain, and storm surge, exploiting the weakness inherent in thousands of properties. However, they also offered stark evidence that we can build defensively and narrow the path of damage. Resilient homes—IBHS FORTIFIED homes—in both North Carolina and Florida survived intact. Such resilience involves key decisions.

Get the roof right

  • Newer roofs fared well in Hurricane Florence and in most areas impacted by Hurricane Michael. IBHS is analyzing asphalt shingle performance following carefully monitored aging in a variety of climate scenarios. Together with our post-hurricane observations, the shingle analysis will lead to a better understanding of vulnerability.
  • Having a sealed roof deck, part of the IBHS FORTIFIED requirements, prevents significant water intrusion if the roof cover is lost, limiting the cascade of further damage.

Openings and connections are critical

  • Garage doors can be a damage multiplier. Wind passing through a buckling door can increase the pressure inside a house, making it more likely to lose the roof.
  • Tying the pieces of the structure together with strong connections is critical to wind resistance. Well-informed building codes based on the latest science should be adopted and enforced in hurricane-prone states.

Storm surge and flooding

  • The options for getting out of the way of rising water are limited to building higher, building elsewhere, or engineering the flow of the water to go elsewhere. These require difficult choices. However, resilience is possible. The basic solutions are both simple and science-based. We must shape our homes in hurricane-prone areas to be resilient against these weather forces.

Weather, Climate & Catastrophe Insight: 2018 Annual Report