Deadly hurricane season set to end
WEST PALM BEACH, Fla. — In August, the waters of the equatorial Pacific cooled, quieting powerful western gales that act as a balm to the tropical Atlantic during hurricane season.
The atmosphere took advantage of the lull, whipping quickly into a violent lather that crashed three Category 4 storms into the U.S., created the longest-lived 185 mph hurricane in recorded history and drowned Houston in a tropical broth 5 feet deep.
The devastating 2017 hurricane season ends today. Its formidable résumé also includes the most named storms since 2012, more than double the normal number of major hurricanes, and an intensity and longevity cyclone score twice as fierce as the 30-year historical mean.
Hundreds of people in the U.S. and Caribbean died in storm-related incidents, although a final tally may not be known until the National Hurricane Center completes its storm reviews. Texas officials said in September about 80 people were killed by Hurricane Harvey. In Florida, 72 people died from Hurricane Irma-related accidents, according to the state’s Division of Emergency Management.
“It’s just one of those seasons where everything went supersonic,” said Chris Dolce, a digital meteorologist with Weather. com. “Everything that was out there just wanted to develop. Every fledgling system decided to become a storm.”
It wasn’t just a La Niña-influenced atmosphere that created the hyperactive season, which began with Tropical Storm Arlene in April and wound down with Tropical Storm Rina on Nov. 7.
Abnormally warm seasurface temperatures and a westward-sitting Bermuda High increased the fuel for the 17 named storms that formed, and pushed them closer to the U.S. as they rode the high’s underbelly as if on a conveyor belt.
Four hurricanes — Harvey, Irma, Maria and Nate — made landfall in the continental U.S. or Puerto Rico. Harvey, Irma and Maria were Category 4 giants at landfall.
Dan Brown, acting chief of the National Hurricane Center’s hurricane specialist unit, said the number of storms threatening land increased the pressure on forecasters this season.
“With a storm out over the open ocean, there may be ships in the way, but when storms are headed toward any highly populated area, we want to make sure people are getting the message and taking the actions they need to take to save their lives,” Brown said.
The first big challenge came with Hurricane Harvey. Born in the deep eastern Caribbean on Aug. 17, Harvey mustered only tropical storm strength before dissipating to a tropical depression and then reforming in the Gulf of Mexico.
The storm became a major Category 3 hurricane on Aug. 24 and rapidly intensified to a Category 4 before making landfall near Port O’Connor, Texas, on Aug. 26. From there, it meandered, dropping more than 60 inches of rain and causing unprecedented flooding in the Houston area.
The National Weather Service tweeted; “This event is unprecedented and all impacts are unknown and beyond anything experienced.”
Still, Brown said Harvey was a well-forecast storm with meteorologists predicting the track, rapid intensification and deluge of rain.
“Our track forecasts this year have set records for accuracy at each of the forecast time periods out five days,” Brown said. “The three most damaging hurricanes — Harvey, Irma and Maria — the track errors were 25 percent lower than the long-term mean.”
Intensity was still a struggle, especially rapid intensification, which is considered an increase in wind speeds of 34 mph or more over a 24-hour period.
Brown said there were an estimated 40 cases of rapid intensification this season. Just six of them were accurately forecast.
Hurricane Maria’s 15-hour rapid intensification from a Category 1 storm to a Category 5 was compared to 2005’s legendary Hurricane Wilma, which took just 12 hours to reach Category 5 status.
Maria landed in Puerto Rico on Sept. 20, strafing the island with 155 mph winds. It wiped out Puerto Rico’s electrical grid, cut water lines and turned green hillsides brown from wind burn. As of Nov. 20 — two months after Maria made landfall — just 46 percent of the island had electricity.