Sally saw top winds increase from 60 to 100 mph in 12 hours, from 5 a.m. to 5 p.m. Monday.
Rapid intensification is especially dangerous when in happens in the 24 to 48 hours before a storm reaches land. That’s because you can go to bed at night anticipating a Category 1, then wake up to a Category 3 major hurricane that brings impacts far worse than earlier anticipated.
And that is exactly what we’ve seen with Sally, Laura and Hanna.
It’s creeping toward land
Sally is moving at 2 mph — slower than the average human walking pace.
The slower a storm moves, the more rain it can drop on a particular area, and the longer severe winds have to weaken infrastructure.
Recent storms that have devastated the US — such as Hurricane Harvey in Texas and Hurricane Florence in the Carolinas — have moved extremely slow, allowing for massive rainfall totals and flooding.
It looks like Sally will follow that trend.
It’s packing a lot of rain
Historic flooding is possible with Sally, the National Hurricane Center said, because of the amount of rain that is forecast over 48 hours beginning Tuesday.
Scientists are very confident the climate crisis is making storm rainfall worse by increasing the rate at which it falls, as well as the amount of rain a storm can produce.
“Simply put, warmer air holds more water vapor,” said Kossin, an atmospheric research scientist at NOAA’s National Centers for Environmental Information.
With Sally, three to four months’ worth of rain could fall before the storm leaves the region Thursday.
CNN meteorologist Judson Jones contributed to this report.