It’s only May, which means the tropical cyclone season in the Northern Hemisphere is still in its infancy. The Atlantic season doesn’t officially start until June 1, after all. Yet already, in just the first four-and-a-half months of the year, the planet has had more Category 5 storms — the most destructive category — than its average annual total of such powerful tempests. So far, five Category 5 storms have formed. The record was eclipsed over the weekend, when Super Typhoon Dolphin became a Category 5 storm in the Northwest Pacific, with maximum sustained winds estimated to be about 160 miles per hour. (The storm is now dissipating and transitioning into a non-tropical storm system.)

The planet averaged just 4.6 Category 5 storms per year between 1990 and 2014. Using a separate metric, this year also appears to be an outlier so far. The accumulated cyclone energy, or ACE index, shows that the Northwest Pacific alone has been running 483% of its typical activity-to-date. This index measures both the intensity and duration of tropical cyclones. FULL REPORT