become far more common in recent years as the planet warms. It was a rare Category 5 for a time Saturday before becoming a Category 4, churning through the Atlantic Ocean north of the Caribbean.

Erin went from a Category 1 hurricane with 75 mph winds at 11 a.m. Friday to a Category 5 with near 160 mph winds just over 24 hours later. It put Erin in the history books as one of the fastest-strengthening Atlantic hurricanes on record, and potentially the fastest intensification rate for any storm earlier than September 1. Erin is forecast to return to Category 5 strength as it undergoes an eyewall replacement cycle, a process that will cause the storm’s windfield to grow in size. Rapid intensification is when a hurricane gains at least 35 mph of wind speed in at least 24 hours. Extreme rapid intensification historically tends to happen in September and October. (CNN)