And the busiest part of hurricane season isn't even over. An analysis of 167 years of federal storm data by The Associated Press found that no 30-year period in history has seen this many major hurricanes, this many days of those whoppers spinning in the Atlantic, or this much overall energy generated by those powerful storms.
Scientists caution it is too soon to draw conclusions from the data, and they don't say the intense activity confirms a trend. Storms in the distant past may have gone unnoticed, which could make earlier generations appear quieter than they were. Some scientists say past hurricane data is so weak that it's impossible to connect the recent activity to global warming.
Georgia Tech climate scientist Kim Cobb said it would be "foolish" for policymakers to ignore the data. "We may not have as much data as we would like, but we have enough to aggressively invest in a variety of defenses for coastal communities," she said in an email. "We face a triple threat of rising seas, stronger winds, and literally off-the-charts rainfall totals."
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Then came this year. Fueled by warmer than normal ocean temperatures and ideal wind conditions, September 2017 had more days with major hurricanes spinning and more overall hurricane energy expelled than any month on record, according to Colorado State University hurricane researcher Phil Klotzbach. Harvey spawned record rainfall. Irma had record high winds in the open Atlantic. And Maria hit the US stronger than the earlier two.
There have been 90 major hurricanes, an average of three a year. That's 48 per cent more than during the previous 30 years. This hurricane season is at five and still counting.