The extreme ferocity of the 2017 Atlantic hurricane season will be talked about for decades. When even one Category 5 forms in the Atlantic Ocean, it is a notable year. Two such storms in the same season are legitimately rare. Hitting land multiple times? Until this year, unthinkable.
As part of a barrage from late August through September, Hurricane Irma blew through records as it plowed across the Northeast Lesser Antilles, the British Virgin Islands and then Cuba as a Category 5. By any account it was a mega-storm, with Category 5 winds of at least 157 mph lasting for days.
Then came Maria. Exploding to behemoth levels as fast as you'll see, it became the first Category 5 to hit Dominica.
Combined, Irma and Maria ended up covering more than 1,500 miles of territory while holding the highest rating for earth's strongest storms. In the process, they rolled past plenty of records, including that of the total distance traveled by Category 5 storms in any Atlantic hurricane season.
A storm like Irma is truly exceptional any year. Hopscotching from one landmass to another, it kept going for days. While watching, I couldn't help but think it was more like a Super Typhoon in the Western Pacific, where the world's strongest tropical cyclones tend to live.
Along its lengthiest stretch as a Category 5 — one that surpassed 1,100 miles — Irma shredded four small islands. As The Washington Post's Jason Samenow later documented in satellite images, the storm made its fifth landfall as a Category 5 on Cuba, during its second go at that intensity.
To further illustrate Irma's record-long, more than 1,100-mile continuous trek over three days, I went into Google Earth and dropped a point on the White House, dragging the resulting path around to see where we might end up. Oddly enough, I found downtown Wichita (oddly, because it is a favorite place of mine for tornado chasing).
Category 5 winds traveled a distance equivalent to almost half the United States. And, for an extended period, Irma's winds were way above the 157 mph threshold for a Category 5. Colorado State University hurricane expert Phil Klotzbach noted that Irma maintain sustained winds of 185 mph for a record-breaking 37 hours.
Following a second and shorter stint at Category 5 along Cuba's northern coast, Irma's cumulative track length at that intensity finished slightly behind Hurricane Allen (1980). Irma's 1,211 miles were just shy of the 1,270 miles for Allen, the record holder.
Despite a slight miss for the longest cumulative Category 5 length on record, Irma's roughly 1,100-mile journey as a Category 5 in its main streak wasn't all that far from doubling Allen's previous record for one segment. It's easy to see in the above chart that the path segment length is a huge outlier across the modern historical record.
With the Caribbean still dazed following Irma's onslaught, Maria sprang to life. Part of a hyperactive stretch that started with Category 4 Hurricane Harvey, and included almost-Category 5 Hurricane Jose, September would ultimately wind up as the most extreme month for Atlantic hurricanes on record.
Sadly, that meant more Category 5 track, and more land hit. This time, Dominica.
The island faced a strengthening Maria — it became a Category 5 right as it roared ashore. After a devastating track across the island, Maria briefly became a Category 4, the main sign of its tangling with Dominica's mountains. Only a few hours later, it was back to a 5 and eyeing the U.S. coastline.
While Maria again diminished to a Category 4 — only 2 mph shy of a Category 5 — just before hitting Puerto Rico, the resulting tragedy was already in motion. With another 300-plus miles of Category 5 track under its belt, the 2017 hurricane season jumped solidly into the lead for the most Category 5 path length on record.
Irma and Maria, together
This season will be remembered as a standout among those rare years in which multiple Category 5 storms formed. Again, much of this is due to Irma's unparalleled main segment. At the same time, it's sort of hard to wrap your head around the fact that there is twice as much Category 5 track this year compared to 2005, a year widely considered the benchmark for the number and intensity of storms.
Given the high toll of this year's season, we'll hope extra hard that we don't add to these numbers before it ends. There are still two months to go.
Disclaimer: Track details are subject to reanalysis and may be changed in the future. In all cases the source here is IBTrACS and the National Hurricane Center. Any differences at the margins (such as GIS projection used in analysis) should not have meaningful impact on results which have been quality checked.