Human-caused climate change increased Hurricane Melissa’s wind speeds by 7% (11 mph, or 18 km/h), leading to a 12% increase in its damages, found researchers at the Imperial College of London in a rapid attribution study just released. A separate study by scientists at Climate Central found that climate change increased Melissa’s winds by 10%, and the near-record-warm ocean waters that Melissa traversed — 1.2 degrees Celsius (1.2°F) warmer than average — were up to 900 times more likely to be that warm because of human-caused climate change.
To study Melissa, the Imperial College of London researchers used the Imperial College Storm Model (IRIS). With the same model last year, the researchers found that climate change increased Hurricane Helene’s wind speeds at landfall by about 11% (13 mph or 21 km/h), and Hurricane Milton’s by 10% (11 mph or 18 km/h). These wind speed increases led to an increase in damage of 44% for Helene and 45% for Milton, they said. Melissa’s relatively low 12% increase in damage with 7% higher winds was so small, they said, because of hurricane of that intensity causes near-total destruction, and there isn’t much more to destroy if the winds increase.
They added that the analysis “likely underestimates the true cost of the hurricanes because it does not capture long-lasting economic impacts such as lost productivity and worsened health outcomes.”
Hurricane damage rises exponentially with wind speed
Although a 10% increase in hurricane winds because of climate change may not sound like a big deal, it matters a lot because hurricane damage increases exponentially with wind speed. For example, according to NOAA, a Category 2 hurricane with 100 mph (161 km/h) winds will cause 10 times the damage of a Category 1 hurricane with 75 mph (121 km/h) winds. This includes damage not only from winds but also from storm surge, inland flooding, and tornadoes. Bottom line: A 10% increase in winds yields about a doubling in hurricane damage (Fig. 1). The exception: once a hurricane’s winds far exceed the 156 mph Cat 5 threshold (as Melissa did), additional damage will not increase as rapidly in regions with relatively poorly-built structures, since there will not be much left to destroy.
Forecast for Melissa
Hurricane Melissa roared through the southeastern Bahamas on Wednesday afternoon and evening, passing near the southern tip of Long Island near 5 p.m. EDT Oct. 29 as a Category 1 storm with 90 mph (150 km/h) winds and a central pressure of 974 mb. Earlier on Wednesday, at 3:10 a.m. EDT, Melissa made landfall in the eastern Cuban province of Santiago de Cuba, about 40 miles (65 km) west of Santiago de Cuba, as a Category 3 storm with winds of 120 mph (195 km/h) and a central pressure of 952 mb. Melissa’s first landfall was in western Jamaica at 1 p.m. EDT Oct. 28, as a Category 5 storm with 185 mph (300 km/h) winds and a central pressure of 892 mb, tying with the 1935 Labor Day Hurricane in the Florida Keys as the strongest landfalling Atlantic hurricane on record.
As of 11 a.m. EDT Thursday, Category 2 Melissa was centered about 515 miles (830 km) southwest of Bermuda, speeding north-northeast at 24 mph (39 km/hr), with top sustained winds of 105 mph (165 km/h) and a central pressure of 965 mb. Satellite imagery showed a storm that was steadily reorganizing, with a prominent eye beginning to appear. Melissa’s wind field has expanded in size, with hurricane-force winds extending out 60 mi. (95 km) from the center. The hurricane will be able to spread tropical storm conditions and wind gusts approaching 100 mph (160 km/h) to Bermuda late tonight, even though the center of the eye is expected to pass about 120 mi. (195 km) to the northwest around midnight, as a Cat 2. A Hurricane Warning is up for Bermuda.
Melissa is expected to transition to a powerful extratropical storm on Friday, and pass within 100 miles of southeastern of Newfoundland, Canada, near midnight Friday, with sustained winds of 75 mph (120 km/h). Newfoundland will be on the weaker left side of Melissa’s center and will miss the storm’s strongest winds, but a flow of moist air in advance of the storm is likely to contribute to heavy rains of 1-3 inches (25-75 mm) over Atlantic Canada on Friday and Saturday, in combination with a separate storm.
One more month of hurricane season to go
There are no new threat areas in the Atlantic to discuss at this time. Typically, about 6% of Atlantic seasonal hurricane activity (as measured by accumulated cyclone energy) occurs in November. The Atlantic hurricane season ends on Nov. 30.
Please donate to Hurricane Melissa relief efforts
In the coming days, you’ll see a number of appeals for Hurricane Melissa relief; please consider donating to one. Some options include the Jamaica Red Cross, the Jamaican government’s official fundraiser, the Global Empowerment Missions’ Hurricane Melissa fund, the GlobalGiving Hurricane Melissa Relief Fund, and Water Mission.
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