From Franklin to Ophelia, ten hurricanes have developed in the last 10 weeks, consecutively, tying a record for most hurricanes in a row. The last time this happened was way back in 1893.
In an average season, we would typically have seen only five hurricanes by Oct. 13, along with five additional named storms of lesser intensity. This year — far from average — there have been 15 named storms from Arlene in April to Ophelia in early October.
Of the 10 hurricanes, five of them became major — Category 3 or stronger on the Saffir-Simpson scale — and three were present in the Atlantic for more than 12 days.
On top of all this, the season produced two Category 5 hurricanes, Irma and Maria. Only five other known seasons have had two or more Category 5s, the most recent of which were 2005 and 2007.
Another way meteorologists quantify hurricane activity is accumulated cyclone energy (ACE). This index is handy because it takes into account the intensity and duration of all of the named storms. Not surprisingly, 2017 is more than notable by this metric, as well.
Through August, ACE was at near-normal levels, but that rapidly changed in September. The month accrued more ACE than any other month on record (175). Sept. 8, alone, accrued more ACE than any other day on record (16.0425).
The month also broke records for most named storm days (53.5), hurricane days (40.25) and major hurricane days (18). Hurricanes Irma, Jose and Maria each generated ACE of 40-plus, which is the first time on record that a season had three 40-plus ACE-makers.
To date, the ACE is at 215 — the fourth-highest value on record for Oct. 13 (only behind 1933, 2004, and 1893) and the seventh-highest value for any entire season.
Of the 15 named storms so far, only four (Arlene, Gert, Lee and Ophelia) had no impact on land, and six made U.S. landfall (Cindy, Emily, Harvey, Irma, Maria and Nate).
This is the first season on record with two Category 4 continental U.S. hurricane landfalls (Harvey and Irma), although there were two high-end Category 3 hurricanes that hit the United States in less than a day in 1933.
For the sake of brevity, we’ll highlight this year’s significant storms — Harvey, Irma, Maria and Nate.
Harvey rapidly intensified to a Category 4 hurricane just as it made landfall north of Corpus Christi, Tex., in August. The storm ended the record 12-year “major hurricane drought” in the United States and caused significant wind and surge damage where the center made landfall.
Then Harvey stalled over Southeast Texas for another several days, unleashing unimaginable rainfall in the Houston and Beaumont areas. The peak measurement of 60.58 inches set a U.S. tropical cyclone rainfall record, but large areas received more than 4 feet of rain.
Irma strengthened to a Category 5 by the time it reached the northern Leeward Islands, which it completely devastated. It then passed just north of Puerto Rico and Hispaniola, raking them with torrential rain and significant wind.
Hurricane Irma made its first landfall in northern Cuba as a Category 5 — their first since 1924 — and then went on to strike the Florida Keys as a Category 4. In its last act, the storm made a third landfall in southwest Florida on Marco Island as a Category 3. After that, it tracked north through the Florida peninsula, causing widespread damage and power outages for millions.
Maria also hit the northern Leeward Islands as a Category 5 hurricane, just 12 days after Irma, then slammed into Puerto Rico. It was the strongest hurricane to hit Puerto Rico in 89 years, and the island has yet to recover.
As of Oct. 11, the vast majority of the island was without power — 84 percent — and 79 percent did not have cell service.
Finally, Nate made landfall over the weekend on the northern Gulf Coast while cruising toward land at over 27 mph, a record speed for any storm in the Gulf of Mexico.
Note: Corrections have been made to some years and figures. Notably, Hurricane Harvey’s peak rainfall was revised down in late September, from 64.58 to 60.58 inches.