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| In a screen grab from a video by storm chaser Reed Timmer, Hurricane Idalia's storm surge smashes into condos in Cedar Key, Florida Wednesday. |
As rain diminishes in North Carolina today, the threat of any further trouble in the United States from Idalia is over.
Damage was extensive in Florida from Idalia, as expected. But it could have been worse, mostly because it hit a rather sparsely populated part of the state.
Severe storm surges wrecked a number of homes and businesses on Cedar Key and in Steinhatchee, along the northwest coast of Florida. Just inland, the town of Perry, population 7,000, was raked by winds gusting to at least 90 mph, shredding roofs, punching through windows, smashing metal buildings, dismantling signs and toppling numerous trees.
Still, things aren't as bad as they could have been. So far, two deaths have been reported. That's bad, but you could have had dozens of fatalities had things worked out differently. Tampa only got a glancing blow. The feared storm surge in Tampa Bay did materialize, but it only caused relatively minor flooding. Though a few businesses right along the shore were badly damaged there.
All in all, it could have been worse.
There were some really interesting things, though regarding Idalia and some worrying trends involving hurricanes, especially those that have been striking the United States Gulf Coast
LAST MINUTE STRENGTHENING
Idalia continued an increasing - and dangerous - trend toward hurricanes rapidly intensifying just before landfall.
Storms like that which quickly ramp up before hitting land can more easily catch people by surprise, sometimes with deadly results.
As Jeff Masters reports, since 1950, only ten hurricanes that made landfall in the United States had their winds strengthen by at least 40 mph within the 24 hours before landfall. Five of those hurricanes (Harvey, Michael, Laura, Idalia and Ida) have occurred just within the past six years.
DID CLIMATE CHANGE CONTRIBUTE?
There have always been powerful hurricanes in the Gulf of Mexico. The water there usually gets quite warm in the late summer.
Most of the time, you need water temperatures of at least 82 degrees to allow hurricanes to form and strengthen. Water temperatures in the Gulf routinely get hotter than that this time of year.
The hotter the water, though, the more a hurricane will strengthen, as long as other meteorlogical factors, like upper level winds cooperate.
Idalia was of course not the strongest hurricane ever to form in the Gulf of Mexico. But it was strong, and it developed incredibly rapidly, as you just read above.
"As far back as 1987, MIT hurricane scientist Kerry Emanuel theorized that the wind speeds in hurricanes can be expected to increase about 5 percent for every 1.8 degrees Fahrenheit increase in tropical ocean temperature, assuming that the average wind speed near the surface of the tropical oceans does not change. Computer modeling has found a slightly smaller magnitude (4 percent) for the increase."
Masters acknowledges that a four to five percent increase in hurricane winds doesn't sound like a big deal. But he says damage increases exponentially with an increase in hurricane winds.
A hurricane with 100 mph winds will do ten times the damage of a minimal hurricane with 75 mph winds, if you take into account destruction from wind, storm surges, inland flooding and tornadoes. "Bottom line: a 4-5% increase in winds yields about a 40-50% increase in the destructive potential of a hurricane," Masters writes.
Gulf of Mexico waters were near 90 degrees along the path of Idalia. It probably would not have strengthened as fast as it did if water temperatures were closer to normal, say 84 or 85 degrees. Climate change is heating the Gulf of Mexico, along with ocean water all over the world.
Climate change was likely not the main driver of Idalia's strength, but it probably contributed some to it.
BEWARE THE "I"S OF HURRICANES
For some reason, hurricanes that start with the letter "I" have historically been especially nasty.
Usually, the same hurricane names are recycled every six years. If you get a nothing burger tropical storm named, say, Arlene, you'll see a storm with the same name pop up six years later.
However the National Hurricane Center retires names of hurricanes if they are particularly memorable and destructive.
Hurricane expert Brian McNoldy recently tweeted (Or X'd?) that of the 13 "I" storms that have been retired in the past 70 years, seven of those names have been retired in just the past 14 years. (Ike, Igor, Irene, Ingrid, Irma, Ida, Ian).
Storms that begin with the letter "I" tend to occur during the middle of the hurricane season, when storms tend to be strongest. So you'd think that storms that begin with "H" and "J" are also frequently retired.
Not so, says McNoldy. Only six "H" storm names have been retired over the past 70 years, and only five "J" storms have been retired during that period.
GULF COAST BATTERED IN PAST 7 YEARS
The United States along the coastline in the Gulf of Mexico has been especially battered over the past seven years. As atmospheric scientist Tomer Burg notes, ten hurricanes, all with top winds of at least 100 mph, have hit somewhere between Texas and western Florida in the past seven years. Seven of those storms had top winds of at least 125 mph.
Burg notes that these Gulf Coast hurricane strikes seem to come in phases in recent years. In the seven years between 2009 and 2016, no hurricanes with top winds of 100 mph or higher struck the Gulf Coast.
However, between 2004 and 2008, eighty hurricanes with top winds of 100 mph or more struck our Gulf Coast.
I don't know what the explanation is for this on and off cycle.
OTHER HURRICANES
It's near the peak of hurricane season, so the Atlantic Ocean continues to bubble with tropical activity. Big Hurricane Franklin is still out there, lumbering east-northeastward heading away from Bermuda. It will gradually weaken over the next several days without affecting land.
Weak little Tropical Storm Jose formed in the central Atlantic Ocean overnight. It has top winds of only 40 mph, and soon will be sucked into the circulation of Hurricane Franklin. Tropical Storm Jose is destined to have a short and lame life. It won't hurt anybody.
Another disturbance has come off the west coast of Africa. It's just a collection of thunderstorms now, but there's a high chance it could become a tropical storm within the next couple of days. Nobody is really sure of its future path, but early indications are it might head northwest, instead of west, which would limit how many places it could eventually hit.
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