SAN JUAN — The 2017 Atlantic hurricane season will long be remembered as one of the busiest and most destructive hurricane seasons on record.
Five named storms and one tropical depression had already formed by the end of July with little fanfare or destruction, but that rapidly changed with ten consecutive hurricanes, most of which were in the news.
Hurricanes Harvey, Irma and Maria all have damage estimates in the tens of billions of dollars, if not more. One island was nearly made uninhabitable, two locations received more than 60 inches of rain, and three Category 4 hurricanes made landfall in the United States following twelve years without a major hurricane landfall in America.
Below is a look at what we will remember most about this devastating season.
1. Maria’s Toll on Puerto Rico
Maria’s Category 4 landfall on the island territory was a worst-case scenario for Puerto Rico. The hurricane knocked out power to more than 90 percent of the island, and largely disrupted cell and water service. At least 51 people were killed by Maria in Puerto Rico alone, although the actual number may be much higher.
Less than eight percent of Puerto Rico’s roads were open and usable a month following Maria’s passage over the island.
Puerto Rico may take years to fully recover from Maria’s destruction and devastation.
2. Maria and Irma’s Impact on the Virgin Islands
Hurricane Irma made two direct landfalls in the British Virgin Islands (BVI), both at peak intensity; one on Tortola and another on Ginger Island.
Damage in the BVI was extensive, and on some islands it was catastrophic. Many buildings and roads were left in ruins.
Winds gusted to more than 85 mph and powerful rainbands dropped more than a foot of rain in St. Thomas in the U.S. Virgin Islands (USVI) due to Irma’s southern and western quadrants. Widespread structural damage was reported across the USVI. Many trees were heavily damaged or uprooted.
The island of St. John was also decimated and could be home to Irma’s worst destruction on American soil.
Irma delivered the first powerful punch to the electrical grid in both the United States and the British Virgin Islands.
Hurricane Maria delivered the second punch to electricity. Some 80 percent of the USVI remained without power more than a month after Maria battered the territory.
Numerous ports were closed following the pair of hurricanes due to structural damage, but have since reopened.
Hurricane Maria’s eyewall passed near St Croix and damaged most structures on the island.
While tropical storm watches were issued for the Virgin Islands due to the threat of Jose, the hurricane stayed far enough away to spare the island chain.
3. Hurricanes Harvey, Irma and Maria End U.S. Major Hurricane Drought
After a 12-year lull in U.S. major hurricane (Category 3 or stronger) landfalls with sustained winds of at least 111 mph, Hurricane Harvey slammed into the central Texas Coast with winds of 130 mph near Rockport, Texas, on Aug. 25. The most recent major hurricane landfall prior to Harvey was in 2005 when Hurricane Wilma made landfall in southwest Florida.
Just when we were hoping to restart another long streak, Hurricane Irma made landfall a few weeks later in the Florida Keys, also as a Category 4 hurricane with winds of 130 mph. Irma made another major hurricane landfall a few hours later in southwest Florida with winds of 115 mph. Before arriving in Florida, Irma’s eyewall also affected the U.S. Virgin Islands when it was a Category 5.
Reset the time clock and here comes Maria just over a week later. Maria made a stunning third American Category 4 landfall on the southeast shores of Puerto Rico with winds of 155 mph.
Satellite imagery of Harvey, Irma and Maria at the point of their Category 4 landfall.
4. Harvey’s Record-smashing Rainfall
According to the NWS in Lake Charles, Louisiana, two gauges in southeastern Texas reported more than 60 inches of rain between Aug. 24 and Sep. 1 as Harvey trudged through the region. This is more than a foot higher than the previous record heaviest storm-total rainfall from any tropical cyclone in the U.S. in records dating back to 1950.
The areal extent to which the rainfall fell in such quantities was also impressive. The chunk of real estate where at least five inches of rain fell would cover most of the state of Florida or stretch from Boston to Washington, D.C. if the rain had fallen there instead.
Rainfall produced by Harvey as it moved through Texas and Louisiana.
(Weather Prediction Center/National Weather Service)
5. Harvey’s Duration Over the U.S. as a Tropical Cyclone
Following landfall near Rockport, Texas, Harvey relentlessly swirled over portions of Texas, Louisiana and the Tennessee and Ohio Valleys for the better part of seven days. Not counting the time that Harvey spent over the Gulf of Mexico after its first landfall, the system spent 117 hours as a tropical cyclone over land, all the while dropping the tremendous amount of rainfall mentioned above.
6. Irma’s Brute Strength Was Not Something We Have Seen Before
Hurricane Irma held on to Category 5 status for three consecutive days in the Atlantic, but even more impressive was that it held on to its peak intensity – 185 mph – for 37 hours which set a world record. Hurricanes of this intensity often undergo fluctuations in intensity, but Irma did not.
Irma’s peak intensity based on wind speed was the second highest in Atlantic basin history only behind Hurricane Allen in 1980, which had winds of 190 mph.
Track history of Hurricane Irma with the area where it was a Category 5 highlighted in red.
Outside of winds, Irma also contained the 10th lowest pressure of any hurricane in the basin. At its peak, the hurricane’s pressure bottomed out at 914 millibars.
7. Irma Depopulated an Entire Island
Hurricane Irma’s direct strike on the island of Barbuda in the eastern Caribbean brought sustained winds of 185 mph with higher gusts, torrential rain and destructive waves. At least 95 percent of the island’s structures – including hospitals, schools, homes and docks – were damaged or destroyed.
Following the catastrophic damage unleashed on the island, the government of Antigua and Barbuda forced a mandatory evacuation of Barbuda, with residents being brought to Antigua. Few residents have made the return trip to Barbuda even months after the evacuation order was lifted due to insecurity on the island, the inability to build new shelter, and local politics.
Before/after images of damage from Hurricane Irma in Codrington, Barbuda, in September 2017. Yellow arrows point to areas with standing water remaining after Irma.
(Digital Globe/Google Earth)
8. September was the Most Active Month on Record, with the Help of Ten Consecutive Hurricanes
September 2017, featuring Category 5 Hurricanes Irma and Maria and Category 4 Hurricane Jose, was the most active month of any Atlantic hurricane season on record in terms of Accumulated Cyclone Energy (ACE).
Generally long-lived, intense hurricanes have a high ACE index, while short-lived, weak tropical storms have a low value. The ACE of a month is the sum of the ACE for each storm and takes into account the number, strength and duration of all the tropical storms and hurricanes in the month.
September generated more ACE than any other calendar month on record, surpassing September 2004, according to Colorado State tropical meteorologist Dr. Phil Klotzbach.
This was about three and a half times the average activity from 1981-2010 in the Atlantic Basin, according to the National Hurricane Center.
Included in September 2017’s ACE calculation were Irma, Jose, Katia, Lee and Maria. All of those except Katia were long-lived hurricanes. Lee and Katia were the only ones to not reach Category 4 or Category 5 intensity at their peaks.
By the time mid-October rolled around, Ophelia became the 10th consecutive Atlantic named storm to become a hurricane in 2017.
That tied the record for the most consecutive Atlantic named storms reaching hurricane strength, which also happened in three other years: 1878, 1886 and 1893, according to Dr. Phil Klotzbach.
9. Tropical-Storm-Force Winds Felt in Most of the Coastal United States and the Caribbean
More than 95 percent of the U.S. Gulf Coast was affected by at least tropical-storm-force winds, or winds of at least 39 mph, this hurricane season.
The numbers are slightly better along the East Coast. More than half of the East Coast saw sustained tropical-storm-force winds with higher gusts, mainly due to Hurricane Irma’s large wind field and Jose’s sideswipe of the Northeast and mid-Atlantic coasts.
Wind fields for all tropical storms and hurricanes this hurricane season.
In the Caribbean, nearly all of the Antilles saw sustained tropical-storm-force winds. Only a few islands completely escaped wind impacts from a tropical cyclone this year: Jamaica, the Cayman Islands, the ABC islands and the Grenadines.
Central America was far safer this hurricane season with respect to winds. Mexico bore the brunt of two hurricanes this year, while Nicaragua and Honduras dealt with Nate’s early phase.
When we begin to talk about overall impacts in Central America, though, their luck runs out. An 800-plus mile wide area of rotation, the source of Nate’s birth, brought very heavy rainfall to a large swath of Central America over a period of a few weeks, resulting in flooding. Earlier in the season, Franklin drenched parts of Mexico and even helped spawn a new tropical storm in the Pacific.
Even Ireland and the United Kingdom picked up tropical-storm-force winds from Ophelia’s post-tropical cyclone phase.
10. Irma’s Many Landfalls
Hurricane Irma made more than a half dozen landfalls along its devastating path. The list below shows the intensity of Irma at the time of each landfall.
- Barbuda: Category 5, 185 mph
- St. Martin: Category 5, 185 mph
- BVI (2 landfalls): Category 5, 185 mph
- Little Inagua, Bahamas: Category 5, 160 mph
- Northern Cuba (possibly a few landfalls): Category 3-4, 125-160 mph
- Florida Keys: Category 4, 130 mph
- SW Florida: Category 3, 115 mph
11. Hurricane Maria Obliterates Puerto Rico’s Radar
Maria’s direct hit on the island territory took its full force out on the island’s main radar. Wind gusts up to 160 mph battered the radar’s protective dome and tore it away from the pedestal.
Perhaps more shockingly, the 30-foot wide radar dish went missing following the storm, likely blown off of its pedestal that is left behind. A second radar on the island was not as badly damaged and is now back up and running.
Close detail shows that both the dome that conceals the radar and the radar dish are gone.
While it may take months to replace the main radar, two U.S. Marine Corps mobile radar units have been temporarily deployed to Puerto Rico while the Federal Aviation Administration radar is being assessed and repaired.
12. Ophelia Smacks Ireland and Britain
While not as impactful as a tropical cyclone, after Ophelia turned into a post-tropical cyclone it brought damaging high winds to parts of Ireland and the United Kingdom.
Numerous locations in Ireland, Wales and Scotland reported wind gusts over 75 mph, and one location in Ireland reported a gust of 119 mph.
Three people died in what was called Storm Ophelia in the U.K. while hundreds of thousands of customers lost power in Ireland alone.
Before Ophelia’s post-tropical cyclone hammered Ireland and the U.K., it became the farthest east Category 3 hurricane on record for the Atlantic Basin.
13. Two Hurricanes Make Landfall Within 55 Miles of Each Other in Eastern Mexico
Hurricanes Franklin and Katia both made landfall in 2017 between Tampico and Veracruz, both in the state of Veracruz.
Katia made landfall as a weakening Category 1 with winds of 75 mph and Franklin also made landfall as a Category 1 hurricane, but with 85 mph winds.
In Franklin’s final landfall, the hurricane brought heavy rainfall to eastern Mexico and soaked Mexico’s interior before spinning off a new tropical storm in the Pacific. Damage in the Veracruz state was largely minimal, but sporadic power outages and a few landslides were reported.
Katia was more damaging in Mexico’s eastern states. Many landslides were reported and 77,000 people lost power during the hurricane. Katia made landfall just days after a major 8.2 magnitude earthquake rattled the southern part of the country, and Katia’s rain helped move loose ground over central and southern Mexico.
Tracks of hurricanes Franklin and Katia.
14. Rapid Intensification Keeps Us on Edge
Rapid intensification is noted by the National Hurricane Center as being one of the most difficult processes to forecast and understand in tropical forecasting. The highest errors in forecasting are often associated with phases of rapid changes in hurricanes.
The 2017 hurricane season produced six tropical cyclones that developed in ideal environmental conditions allowing rapid intensification to occur. This is defined as an increase of wind speeds by 35 mph in 24 hours.
- Harvey: 35 mph to 130 mph; Late Aug. 23 – Aug. 25
- Irma:
- Round 1: 50 mph to 115 mph; Midday Aug. 30 – early evening Aug. 31
- Round 2: 120 mph to 185 mph; Midday Sep. 4 – mid-afternoon Sep. 5
- Jose: 90 mph to 150 mph; Midday Sep. 7 – midday Sep. 8 [Explosive intensification]
- Katia: 35 mph to 80 mph; Late Sep. 5 – late Sep. 6
- Lee: 50 mph to 90 mph; Late Sep. 23 – late Sep. 24
- Maria: 50 mph – 160 mph; Early Sep. 17 – evening Sep. 18 [Explosive intensification]
15. Tropical Systems Produce Most U.S. Tornadoes in Nearly a Decade
Five tropical cyclones were responsible for 119 reports of tornadoes in a dozen states, according to preliminary data provided by NOAA’s Storm Prediction Center (SPC). This includes two tropical storms (Cindy and Philippe) and three hurricanes (Harvey, Irma and Nate).
Hurricane Harvey had the largest number of tornado reports with 57, mostly clustered near the southeastern Texas coast. Tornadoes were also spawned by Harvey as it weakened to a tropical storm and a tropical depression in Louisiana, Mississippi, Alabama and Tennessee.
Plotted on the map are the tornadoes associated with the hurricanes and tropical storms that affected the U.S. in 2017.
The 2017 hurricane season produced the largest number of reported tornadoes spawned by tropical storms and hurricanes in the continental United States since 2008, and the fourth-most overall in 23 years.
16. Hurricane Irma Pushes Water Out of Tampa Bay While Slamming the East Coast with Storm Surge
As Hurricane Irma entered the state through the Florida Keys, residents of Tampa Bay noted something peculiar: The bay was emptying.
Three to six feet of water was pushed out of Tampa Bay by northeast winds ahead of Irma’s eyewall, surprising residents on Tampa’s famous Bayshore Boulevard, a street that typically floods in hurricanes, heavy rain events and even strong cold fronts.
This go-around, however, residents were able to precariously walk out onto the dry seabeds of Tampa Bay. These residents had to rescue manatees on the muddy seabed after they were also surprised by the disappearance of Tampa Bay.
A depiction of Irma’s storm surge pattern as the hurricane entered the peninsula and moved northward through the state. Irma’s path is shown in gray.
On the flip side, numerous feet of storm surge piled up along much of Florida’s Atlantic shoreline and surprised residents well inland on the First Coast.
A storm surge at Virgina Key, in Biscayne Bay, was close to 4 feet above normal tides while the middle keys experienced a storm surge of more than 10 feet. A storm surge of 2 to 4 feet was recorded in northeast Florida, including along much of the St. John’s River near and south of Jacksonville well inland from the Atlantic.
More than 26 river gauges reached or exceeded major flood stage across northern Florida – and Jacksonville’s St. Johns River reached its highest level ever. Gauges remained higher than normal for weeks following Hurricane Irma due to the river’s slow movement.
Irma’s large wind field also forced water inland along the coasts of Georgia and South Carolina. The combination of extremely high tides, storm surge and heavy rain resulted in dangerous flooding in Charleston, South Carolina, where inundation exceeded the levels brought by Hurricane Matthew just a year earlier.
Record flooding was also observed at the St. Simons Island Pier in Georgia due to storm surge and heavy rainfall.
17. Arlene Starts the Season Early
Arlene’s early formation on Apr. 20 was not only more than a month before the beginning of hurricane season, but was also the second earliest-forming tropical cyclone in the Atlantic in the satellite era (or since 1966).
This was the third consecutive year a system has formed in the Atlantic before the official June 1 start of the hurricane season.
Track history of Tropical Storm Arlene from April 19-21, 2017.
On a long-term average, a tropical system forms prior to June about once every 10 years, and these storms tend to be relatively weak, due in part to cooler sea-surface temperatures.
There has been a recent trend in early starts to the Atlantic hurricane season, with 2012, 2015 and 2016 all reporting tropical cyclone formation before June 1.
