WITH vicious winds gusting at 120mph, the hurricane that made landfall in Puerto Rico on September 20th 2017 was expected to be deadly. Hurricane Maria wrought destruction across the island, cutting power, communications and drinking water to nearly every home. Yet most of the 3.3m islanders appeared to escape the worst fate: two weeks later, the official death toll reported by the island’s government was just 16 people.

President Donald Trump made much of the low death count when he visited San Juan on October 3rd. “We’ve saved a lot of lives…If you look at a real catastrophe like Katrina and the hundreds that died…16 versus literally thousands of people…you can be very proud.” Although the death toll rose slowly over the weeks that followed, from 16 to 64 deaths, it remained surprisingly low given the severity of the storm.

Suspicious that the true figure was higher, several others attempted a better guess. In December the New York Times analysed mortality reports and reckoned that the hurricane had killed as many as 1,052 people in the period to October 31st. A paper published in the New England Journal of Medicine in May surveyed hurricane survivors and calculated that anywhere between 793 and 8,498 people had perished.

The island’s governor, Ricardo Rosselló, was suspicious of the official toll, too. It mostly counted direct deaths from flying debris and the like, overlooking deaths from power cuts and lack of water that led to medical complications. In February Mr Rosselló commissioned an independent report by epidemiologists at George Washington University to arrive at a more accurate count.

That report was released on August 28th, fully 342 days after the hurricane made landfall. The academics calculated a final figure based on the observed excess mortality over and above what might be expected in normal weather. In total they rest on a final death count of between 2,658 and 3,290. That would make Maria the worst hurricane to affect America for 118 years (see chart).