The thirteenth named storm of the 2016 Atlantic hurricane season, Hurricane Matthew, the longest-lived Category 4-5 in October in the Atlantic, attaining a lifetime maximum intensity of Category 5. It reached a maximum Category 3 intensity while tracking parallel to the Florida coastline. It then made a brief landfall in South Carolina on October 8th as a Category 1 intense hurricane. Hurricane Matthew recorded peak gust winds at 109 mph at Cape Canaveral, FL, 91 mph at Daytona Beach, FL and 69 mph at Charleston, SC. Along the coast of Florida, Georgia and South Carolina, a storm surge of four to eight feet was reported.
Willis Re’s damage reconnaissance team spent two days in the field assessing Matthew’s damage. The objective was to research and to collect examples of property damage due to wind, and identify elements of properties that exhibited good and poor resistance to hurricane wind forces. Due to various challenges accessing all of the damaged areas, we focused on various properties exposed to the storm in these Florida locations:
- Daytona Beach
- Port Orange
- St. Augustine
- Ormond Beach
Damage from wind
In general, the direct damage to insured properties due to the wind component of the hurricane was minor in the surveyed areas. However, in a few highly localized areas, we observed minor to moderate wind damage.
Overall, we observed minor damage to buildings from Hurricane Matthew’s direct winds. However, we did see moderate damage to roofing and wall siding in a few localized areas, as well as property damage due to tree fall in limited cases. Based on our observations of the patterns of damage and tree coverage in the damage study regions, it appears that tree coverage shielded surrounding homes from severe wind gusts.
Our team visited four mobile home parks in the study region. All surveyed homes are located in manufactured home parks and are double-wide. Damage to the homes themselves was largely limited to loss of shingles and minor siding damage. Direct wind damage was largely limited to add-on structures such as carports, screen enclosures and utility sheds.
Since, in almost all observed cases, the carports were not structurally connected to the mobile home, we observed carport roof covers cleanly peeled off by wind forces. This caused none to very minor additional damage to the main structure.
For more than 70% of surveyed homes, homeowners tied their carport frame to the ground using straps and permanent metal wires that provided additional strength against uplift.
Of all surveyed damaged mobile homes, 27% experienced some damage to carports and other add-on structures only, 27% homes experienced damage to add-on structures and roof. We did not observe damage to mobile home tie-downs or foundations.
In 73% of cases where damage to the roof of the primary structure was observed, it was limited to the loss of few shingles along the ridges and corners (i.e., very minor roofing damage).
Single-family dwellings and low rise buildings
The Willis Re team also saw minor damage to roof shingles on single-family dwellings and low-rise commercial buildings. Generally, aged and weathered shingles hold little sealant bond strength and exhibit poor resistance to wind uplift force. Because of this, homes that have aged roofs tended to lose relatively more shingles (e.g., flipped and missing shingles) than buildings with newer roofs.
The damage to high-rise beach-side condominiums and commercial buildings we saw included damaged window panes, loss of wall stucco/plaster and damage to exterior insulation finish (EIFS). We knew that historically, non-load bearing exterior wall cladding systems (EIFS) perform poorly against hurricane wind forces, but Matthew’s damage exposed EIFS weakness again. Due to the required workmanship and challenges associated with repairing these high-rise buildings, the cost of repairs can be high.
Willis Re’s Catastrophe Analytics team hopes to collect additional building damage data from wind and storm-surge-impacted areas in South Carolina, Georgia and Florida. In the coming weeks we will evaluate all the scientific data, observations from our field surveys and other information available for this event. We are confident that the results of this detailed study, in conjunction with insurers’ actual claims data from Hurricane Matthew, will be helpful as companies make business decisions in the future.