Some of the main ways that scientists believe global warming is influencing hurricanes and making their impacts worse — Hurricane Sally looks to be checking all of those boxes. Here's a look at how the climate crisis could be impacting the storm:
Hurricane Sally officially "rapid intensified" on Monday, a term that refers to a storm’s maximum sustained winds increasing at least 35 mph in 24 hours or less, according to the National Hurricane Center.
Sally saw top winds increase from 60 mph to 100 mph in 12 hours, from 5 a.m. to 5 p.m. Monday.
Rapid intensification is one of the ways scientists believe climate change is impacting hurricanes, with warmer waters helping storms to grow stronger and do so faster. Hurricanes Hanna and Laura also rapidly intensified earlier this year before making landfall in Texas and Louisiana respectively. Rapid intensification is especially dangerous when in happens in the 24 to 48 hours before a storm reaches land — and that is exactly what we have seen with Sally, Laura and Hanna this year.
Sally is moving at 2 mph — slower than an average human walking pace.
Hurricanes and tropical storms are moving slower around the planet, says a study from National Oceanic and Atmospheric Administration scientist James Kossin, who analyzed hundreds of storms in all basins over decades.
The slower a storm moves, the more rain it can drop on a particular area, and the longer severe winds have to weaken infrastructure.
The 2018 study in the scientific journal Nature showed a 10% decrease in forward speed globally between 1949 and 2016, though there is some variation among ocean basins. 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 Hurricane Sally will be another storm with that trend.
Historic flooding is possible with Hurricane Sally, according to the National Hurricane Center, because of the amount of rain that is forecast over the next 48 hours.
Scientists are very confident that climate change 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,” according to Jim Kossin, an Atmospheric Research Scientist at NOAA’s National Centers for Environmental Information.
The Gulf of Mexico water temperatures are largely above average and the Northern Hemisphere has just finished its hottest summer on record, which allows storms like Sally to hold more moisture and produce more rain. With Sally, projections are for 3-4 months’ worth of rain before the storm leaves the region on Thursday.