Top Ten 2015 Atlantic Hurricane Season Events; Paris Climate Talks Ramp Up

The 2015 Atlantic hurricane season is officially over, and it will go into the books as the most memorable hurricane season to occur during a strong El Niño event. Strong El Niño events typically reduce Atlantic hurricane activity by increasing wind shear over the tropical Atlantic, and this year's El Niño conditions did indeed create unusually high levels of wind shear over the Caribbean, making it difficult for tropical systems to organize and strengthen in those waters. According to Colorado State's Dr. Phil Klotzbach, the 200-850-mb vertical wind shear in the Caribbean (10-20°N, 90-60°W) averaged from June through October was the highest since at least 1979 (28.5 knots.) However, this high wind shear did not extend as far east as usual, allowing several tropical storms to form near the coast of Africa over waters that were near-record warm. Near record-warm to record-warm ocean temperatures were also over more northern reaches of the Atlantic, and helped spur the formation of Hurricane Joaquin and Hurricane Kate. As a result, the 2015 season was able to tally numbers that were not that far below average--11 named storms, 4 hurricanes, and 2 intense Category 3 or stronger hurricanes. The 1981-2010 average numbers were 11.5 named storms, 6.1 hurricanes, and 2.6 major hurricanes. Accumulated Cyclone Energy (ACE) is a measure of the total destructive power of a hurricane season, based on the number of days strong winds are observed. ACE for an individual storm is computed by squaring the maximum sustained winds of the storm at each 6-hourly advisory, and summing up over the entire lifetime of the storm. The ACE for the 2015 Atlantic hurricane season was about 60% of average, reflecting the relative lack of hurricanes. Hurricane Joaquin accounted for 46% of the season's ACE.


Figure 1. Preliminary paths of all the named Atlantic storms of 2015, except for Hurricane Kate, which has not yet been added. Image credit: NOAA/NHC.


Figure 2. Vertical wind shear across the Caribbean averaged from June through October for each of the years 1979 through 2015. Wind shear in 2015 was the strongest on record. Image credit: Phil Klotzbach's and Bill Gray's November 30 season summary (CSU.)

Top ten notable events of the 2015 Atlantic hurricane season
Here's my top-ten list of events of the 2015 Atlantic hurricane season--some of them taken from Colorado State's Dr. Phil Klotzbach's November 30 summary:

1) Hurricane Joaquin was the strongest Atlantic hurricane since 2007, topping out just below Category 5 strength on October 3 with 155 mph winds. Joaquin was the second deadliest and second most damaging Atlantic named storm of 2015, causing $100 million in damage in the Central Bahamas, where it lingered for several days. Joaquin's death toll was 35, with 33 of these deaths occurring from the sinking of the ill-fated cargo ship El Faro. Although Joaquin tracked far to the east of the United States, a non-tropical low over the Southeast tapped into the hurricane's moisture, causing record-shattering rains and flooding across North and South Carolina. Several areas of South Carolina saw accumulations exceeding the threshold for a 1-in-1,000-year event. The subsequent floods inundated large areas of the state, killing 19 people and causing over $2 billion in damage.


Figure 3. Hurricane Joaquin as seen by the GOES-East satellite at 7:45 am EDT October 1, 2015. At the time, Joaquin was an intensifying Category 2 storm with 110 mph winds. The last position of the cargo ship El Faro, in the northwestern eyewall of Joaquin, is shown. Image credit: United States Navy and NOAA.

2) Tropical Storm Erika was the deadliest and most expensive Atlantic storm of 2015. Erika unleashed a catastrophic deluge on August 27 that brought extreme flooding to the Caribbean island of Dominica (population 72,000), causing its most expensive disaster in history. The storm did $612.7 million in damage in East Caribbean dollars to roads and bridges, $39.5 million in damage to the airport, and an additional $12 million in clean up costs (thanks go to David C. Adams of Thomson Reuters for this info.) Erika's total preliminary price tag of $275 million U.S. dollars is not far from Dominica's annual GDP of $500 million. The storm will likely set the island back 20 years in development, Prime Minister Skerrit said. According to EM-DAT, the international disaster database, Dominica's previous most expensive disaster was the $175 million in damage from Hurricane Marilyn of 1995. Erika's death toll of 36 makes it the 3rd deadliest disaster in Dominica's history, behind the 40 killed in 1979's Hurricane David and the 2,000 people killed in Dominica by The Dominican Republic Hurricane of 1930.


Video 1. Floodwaters rage through a street on Dominica island in the Caribbean on Thursday, August 27, 2015, after Tropical Storm Erika dumped 12+" of rain on the island.

3) Hurricane Fred. For the first time since 1892, a full-fledged hurricane pounded the Cape Verde islands, when Hurricane Fred intensified to a Category 1 storm with 85 mph winds as it passed through the islands on August 31. Fortunately, Fred missed making a direct hit on any of the islands, and damage was less than $2 million. However, Fred brought violent seas to the West African coast, damaging or destroying numerous fishing villages in Senegal. Between the coasts of West Africa and Cape Verde, maritime incidents related to Fred resulted in 9 deaths (Wikipedia.) Fred became a hurricane at 22.5°W longitude, the easternmost formation location in the tropical Atlantic for any hurricane in the historical record. The previous record was held by Hurricane Three of 1900, which became a hurricane at 23°W, south of the Cape Verde islands.


Figure 4. MODIS image of Hurricane Fred from NASA's Terra satellite taken at approximately 11:15 am EDT Monday August 31, 2015. At the time, Fred was at peak strength with top sustained winds of 85 mph. Image credit: NASA.

4) No major hurricanes made US landfall in 2015. The last major hurricane to make US landfall was Wilma (2005), so the US has now gone ten years without a major hurricane landfall. In records going back to 1851, the US has never had a ten-year period without a major hurricane landfall, eclipsing the previous record of eight years set from 1861-1868.

5) Florida went without a hurricane impact for the 10th consecutive year. This is the longest consecutive year period on record that Florida has not had a landfall since records began in 1851. The longest previous record was five years, set from 1980- 1984.

6) Ocean temperatures in the Caribbean were the warmest on record in October, yet no storms formed in the Caribbean and only one (Erika) tracked into the Caribbean. This is because June-October-averaged 200-850-mb vertical wind shear in the Caribbean (10-20°N, 90-60°W) was 28.5 knots--the strongest on record (since 1979).

7) Hurricane Danny. Despite strong El Niño conditions developing in the Eastern Pacific, a major hurricane managed to form in the Main Development Region (MDR) of the tropical Atlantic, between the coast of Africa and the Caribbean. Hurricane Danny only lasted six hours as a major hurricane, and high wind shear and dry air destroyed the storm just as it arrived in the Lesser Antilles Islands.


Figure 5. Hurricane Danny as viewed from the International Space Station and tweeted on Thursday morning, August 20, by astronaut Scott Kelly. At the time, Danny was an intensifying Category 1 hurricane with 80 mph winds. Image credit: NASA.

8) Only four hurricanes formed in 2015. This brings the combined 2013-2015 total to 12 hurricanes. This is the lowest three-year total since 1992-1994 (11 hurricanes).

9) Two major hurricanes formed in 2015. This brings the combined 2013- 2015 total to 4. No three-year average has been lower since 1992-1994 (2 major hurricanes).

10) Hurricane Kate became the Atlantic’s most intense tropical cyclone on record for November during the five years since 1950 with strong El Niño conditions present in October-December: 2015, 1997, 1982, 1972, and 1965. Only one other named system was observed during those Novembers: 1972’s Subtropical Storm Delta.


Video 1. WU member Brian Osborne created this impressive 18-minute long video of over 10,000 GOES-East images showing the evolution of the 2015 Atlantic hurricane season. Particularly interesting is the portion about 12 minutes in, when we see Hurricane Joaquin form, plow into the Central Bahamas, then turn a firehose of moisture into South Carolina that gets wrapped around an upper-level low pressure system.

Day 1 of the Paris climate summit: Leaders weigh in
More than a week of tough negotiations lies ahead at the UN Climate Conference (COP21), but Monday--the opening day--was a time for reflection and expression of common purpose. More than 150 heads of state were on hand, and dozens of them gave speeches, acknowledging the gravity of human-produced climate change and the daunting task of turning it around. These themes were delivered in many flavors. Canada’s new prime minister, Justin Trudeau, stayed upbeat while alluding to his nation’s having bowed out of the Kyoto Protocol: “Canada is back, my friends. Canada is back, and here to help.” France’s president, Francois Hollande, was understandably grave: “...never have the stakes been so high because this is about the future of the planet, the future of life. And yet two weeks ago, here in Paris itself, a group of fanatics was sowing the seeds of death in the streets.” British Prime Minister David Cameron brought the issue to a familial scale--“Let’s just imagine for a moment what we would have to say to our grandchildren if we failed”--while the prime minister of Slovenia, Miro Cerar, harked back to a quote by the late US president Dwight Eisenhower: “As we peer into society’s future, we--you and I, and our government--must avoid the impulse to live only for today, plundering for our own ease and convenience the precious resources of tomorrow.”

As in past summits, some of the most poignant remarks came from the leaders of island nations threatened soonest by rising sea levels and storm surge. Marshall Islands president Christopher Loeak put it this way: “The climate we have known over many centuries has in a matter of three short decades, changed dramatically, before our very eyes. We are already limping from climate disaster to climate disaster and we know that there is worse to come. For us, COP21 must be a turning point in history. And one that gives us hope.” Many of the smaller island states are maintaining their longtime push to keep global warming at no more than 1.5°C above preindustrial levels--perhaps a quixotic goal at this point, given the record global warmth of 2014 and 2015 and the possibility that 2016 will be warmer still. On the brighter side, India announced on Monday that it will spearhead a new global alliance of 120 nations aimed at vastly expanding the reach of solar power to developing towns and cities across the tropics. The new alliance will serve as a framework through which agencies and industry can take advantage of economies of scale in bringing solar power to underserved areas. Although restricting fossil fuels is sometimes viewed as a roadblock to economic development for the world’s poorest residents, it’s quite possible that initiatives like these could be just the opposite--a way to leapfrog over current logistical barriers and move directly toward clean, accessible power.

See our Monday post for more on the Paris summit, including links to frequently updated news sources. Wunderground's climate change blogger, Dr. Ricky Rood, has an interesting new Tuesday afternoon post on the Paris climate summit called All Fracked Up.

Our next post will be Wednesday or Thursday.

Jeff Masters (tropical], Bob Henson [Paris summit]


Figure 6. The Eiffel Tower was lit up in green on November 30 during the first day of the United Nations climate conference in Paris. Image credit: Stephane de Sakutin/AFP/Getty Images.