During periods of greater Atlantic hurricane activity, a protective barrier of vertical wind shear and cooler ocean temperatures forms along the U.S. East Coast, weakening storms as they approach land, according to a new study by NCEI scientist, Jim Kossin. In his paper, “Hurricane Intensification along United States Coast Suppressed during Active Hurricane Periods” published in Nature, Kossin identifies this “buffer zone” and describes its relationship with both active and inactive periods of Atlantic hurricane activity.
Hurricanes depend on warm sea surface temperatures to power their warm cores with heat and moisture. But, vertical wind shear—changes in wind speed and direction from the surface to the top of the troposphere—removes the heat and moisture from a storm’s center, potentially breaking it apartcompletely. In the tropical Atlantic, where hurricanes develop, sea surface temperatures and vertical wind shear act together to either enhance or hinder hurricane intensification.
“During periods of greater hurricane activity, the sea surface temperatures are warmer and the wind shear is weaker in the tropical Atlantic,” says Kossin. “Likewise, during periods of low activity, the sea surface temperatures are cooler and the wind shear is stronger there. But, the opposite is true when we look near the U.S. coast. When conditions in the tropical Atlantic are good for hurricane intensification, they are bad for it near the coast and vice versa.”
So, when the environment is good for making strong hurricanes in the tropics, those hurricanes crash into more hostile conditions if they approach the U.S. coast, which weakens them. In this way, the pattern creates a hurricane buffer zone along the coast during periods of high activity. According to historical records from 1947 to 2015, hurricanes were roughly twice as likely to intensify along the U.S. East Coast when the buffer zone wasn’t present. And, they were two to three times more likely to rapidly intensify—by 15 knots or more in 6 hours—without the wind shear and ocean temperature buffer.
The absence of the buffer zone had an even greater impact on major hurricanes. Without it, major hurricanes were two to four times more likely to intensify and three to six times more likely to intensify rapidly. This presents major implications for forecasters, as rapid intensification near the coast is difficult to predict and shortens public warning time.
The period of high Atlantic hurricane activity over the past 20 years and the accompanying development of the buffer zone may help explain the present “drought” of major hurricane landfalls in the United States. The buffer also may have come into play when Hurricane Matthew headed toward the country. While Matthew’s rains were devastating for some areas, the buffer zone helped weaken the storm from a Category 4 as it advanced on Florida to a Category 1 when it officially made landfall in South Carolina. By keeping higher wind speeds at bay, the buffer zone likely helped prevent further compounding damages from Matthew.
In light of how the buffer zone affects coastal communities, scientists aim to further study its relationship with hazard risk in these areas.
When the Delta Skymiles American Express sign up reward of 60,000 bonus miles hit my account, I immediately began plotting my next free adventure.
Though I’ve spent much of my time in the land I call home– home to my clan and my heart– I couldn’t think of a better way to spend some free miles. While most transatlantic flights cost 100k+ miles, by keeping my dates flexible and booking three months out I was able to get round trip from my home in Fort Myers to Aberdeen for that 60K. Three weeks in my favorite place in the world, the #1 safest place for a woman to travel alone? Absolutely! Let’s go!
I planned on camping most of the trip to conserve funds, but a distant cousin who was gun shy on solo travel and who had always wanted to go to Scotland asked if I would show her about during my time here, so I agreed. She picked up the tab for hotel rooms for herself with an extra bed, just in case I didn’t want to camp out the entire time, and I gave her an itinerary of my schedule.
While I always keep my plans fluid because I often indulge in whims, for the first week I planned to start around my favorite area -Inverness- and camp in a twelfth century castle known as Rait in the Highlands just south of Nairn on the Moray Firth, as well as my Cousin’s castle at Balvenie, then I planned on going to Orkney to visit neolithic sites and finally to the Hebrides and our home Isle of Skye as well as Lewis and Harris in the Western Hebrides. The standing stone circle at Callanish is a killer place to be on the Equinox!
Three months later, here we are. I’m camping Rait Castle outside Nairn. It’s a ruin dating back to the twelfth century which is now public access, coincidentally lying on the property of the Earl of Cawdor. Well off the beaten path, hardly anyone knows of the place, but its’ completely intact tower turret is an ideal place to shelter from the elements with a wee bit more protection from the elements than a tent, as Scottish weather is quite fickle in September. The views here over the Moray Firth are a huge bonus, especially during the gloaming and the autumn months.
Though in September I don’t have the luxury of the extended gloaming that occurs during the early summer months (18-20 hours of daylight this far north) there’s still plenty of time and warm weather left!
I’ve been lucky. The weather was exemplary, and thanks to my free second bag checking from Delta and American Express, I was able to cart over most of the things I’d need to camp successfully, and I bought the rest after I picked up my Peugeot at the Aberdeen airport. I’ll pass off the tent, sleeping bag and air mattress to a homeless person in Glasgow before I leave the UK.
So back to Rait. The castle is supposedly haunted, cursed; the MacKenzie clan and Campbell clans agreed on a banquet 800 years ago to end clan infighting and the Campbells, similarly to what they did at Glencoe, planned on murdering the lot of the Mackenzies. No one counted on the
MacKenzie heiress and Campbell Laird’s son trysting. When they were caught at it, the MacKenzie lass fled and was chased above stairs by her father. At some point during her attempt to escape she decided to go out a window and try to climb down.
Unfortunately the second story is quite high up with lots of rocks below, and her father decided to chop off her hands. She fell to her death and is rumoured to still haunt the place. The few locals who have either managed to spot Rait hiding in the woods off the B9101 or heard about it and trackedit down (It took me some effort the first time!) have either come up for an hour at night on a dare, or disregarded the fact that it’s one of the best preserved examples of a Scottish tower/hall-house left in the Highlands today. Ghost or not, it’s a special place and I’m happy to add it to my list of exotic locales camped! I made sure as always to leave a dead fire and a totally void space where I stayed.
I haven’t encountered the ghost, though. Not on any of my previous visits, nor the whole time I’ve stayed here, a Scottish American princess living in her very own castle. I can’t say I’m disappointed nor can I say it wasn’t a bit creepy a couple of times– that’s why building a fire is so important to boost morale, especially when you’re alone and staying in such a place!
Attached are photos of Rait, my tower room, and various other tidbits and from the Highlands around Inverness, including the Nairn beach and Balvenie Castle. I wasn’t joking about how not even locals know the place… most people I’ve met when I tell them where I’m camping do a double take and ask where, then say they’ve never heard of it. The only persons I’ve encountered during my stay at Rait were a photographer jockeying for shots of the Northern Lights when tipped off by AuroraWatchUK, and a sweet older gentleman who is set to show the place to some Americans with the surname of Rait at the end of the month. It’s been peaceful and quiet and beautiful, hadn’t cost me a nickel, and was the break from reality I sorely needed!
Waking up daily to gaze at ships coming into the Moray Firth from the North Sea… the birds singing and the mists rolling through the heather and gorse… it’s isolated yet enriching in a way I cannot describe. My cousin can have her hotel room in Inverness 20 minutes West. This is the way to see the Highlands! While I pride myself on camping in unusual locations, nothing, not even a deserted island in the Caribbean I camped on in 2012, could have prepared me for how wonderful this is. I highly recommend it… with the proper gear, protection and survival training. Things like gathering firewood in an area known for little timber… not easy. It helps to be as prepared as possible and to have contingency plans!
So far, though, it’s been utterly brilliant.
Next week...part two: where to go and what to do in Scotland! Until then Saints Mhath! (Scots Gaelic toast to good health)