Last year, on November 12th, I wrote about the end of that year's hurricane season. This year, I am writing a week later. In 2011, by November 12th, I was guessing that the year's tropical storm and hurricane season would be finished, although it officially runs until the first of December. This year, I was a bit more cautious because the most damaging and unexpected storm of the year came late. But it looks like the season has settled down for now.
I could, if I was so inclined, cut and paste what I wrote last year. Entire paragraphs of that description apply to this year as well. It did follow a normal pattern, with early Caribbean storms followed by the Cape Verde season, with a return to Caribbean storms late in the season. It had a very high number of tropical storms, tying for second place with nineteen named storms. Ten of these developed into hurricanes. In something of an anomaly, only one of these turned into a major hurricane, the harmless mid-Atlantic storm Hurricane Michael. It also had two tropical storms forming before the official June 1st start of the season, and it had a very long-lived storm in Nadine, which wandered around harmlessly in the mid-Atlantic for twenty days.
But the season will be remembered by most as the season of Hurricane Sandy, the late-season, Caribbean storm that hit Haiti and Cuba, and then traveled up the Atlantic Seaboard, hitting an early cold front and becoming a hybrid storm that hit New Jersey and New York around Halloween. The course of Hurricane Sandy was much like 2011's Hurricane Irene, but whereas Irene mostly did damage inland with flooding, Sandy's biggest damage came from its high storm surge, which wiped out entire communities in New Jersey, and flooded lower Manhattan. The damage from Sandy will come to hundreds of lives lost, and tens of billions of dollars.
One of the most important observations I can make on the season was a blurb I read from ABC News, while Sandy was still off the coast of Florida. The news report said that Sandy looked to be the first hurricane in a "remarkably quiet season". Actually, at that time, the season was already tied for second place in the number of storms formed. Although there had not been any large destructive hurricanes, it seems that there is a "new normal" when it comes to evaluating seasons. But as seen with Sandy, the fact that many of the tropical storms are small, wet and not as destructive as a Hurricane Katrina or a Hurricane Andrew is not a sign that we are safe.
And once again, we don't know whether 2011 and 2012 are signs of things to come, or just anomalies. But if this is a matter of anthropomorphic climate change, and not just fluctuations in El Nino, La Nina or the jet stream, then we have paid another 50 billion dollars for this particular data point.