Official counts are obviously more difficult to perform than my anecdotal one, and not just because of scale: Further complicating the picture are mismatched systems in hospitals and morgues that might double-count some victims or misidentify others, as well as tough decision making over just what counts as a hurricane-related death. In its survey of more than 3,200 Puerto Rican households, the team behind the new study tried to get around those difficulties by asking families directly about the deaths of loved ones.

As The New York Times explains, the respondents reported that “38 people living in their households had died between Sept. 20, when Hurricane Maria struck, and the end of 2017.” When extrapolated to the island’s population of 3 million people and compared with deaths from the previous year, the researchers found 4,645 so-called excess deaths over that roughly three-month period. The researchers believe even that number might be low because of various biases in their survey, including their inability to measure any single-person households whose occupant died.

Of the deaths linked by household members directly or indirectly to Hurricane Maria, the largest mortality category was people who died from interruption of necessary medical services—about one-third of the recorded deaths. The survey also found a significant degree of storm-related migration; 3 percent of households had a member leave after the storm. Most of the migrants were young, with an average age of 25, and many were destined for the mainland United States. Additionally, many households reported major barriers to basic services, such as water, electricity, phone service, and medical care.

As The Times notes, these estimates have a rather high margin of error, owing to methodological constraints; the low end of the range reaches down to 800 deaths and the high end reaches as many as 8,000. Two other analyses of estimated mortality following the hurricane found just over 1,000 deaths.

But while this survey isn’t the definitive count of exactly how many people were killed by Hurricane Maria, what it does show with clarity is that the storm was on par with other recent natural disasters that have shaken the American populace and still reverberate today. For example, the official death toll for Hurricane Katrina in 2005 was just over 1,800 people, and it also kicked off a mass migration of displaced residents. Immediately after that storm, New Orleans lost half its population, and it appears that somewhere north of 100,000 people from the city and its surrounding areas have permanently resettled in the years since. Katrina also fundamentally shaped public policy, sparking conversations on climate change, disaster risk management, environmental justice, racial equality, and class.

Hurricane Maria looks increasingly like Katrina in terms of its effects. At the lower end of the Harvard researchers’ death range, it could match Katrina’s toll, and at the higher end, it could eclipse it. If the true death count is closer to 8,000, the September storm would be the single most devastating natural disaster to hit the United States since the Galveston hurricane in 1900.