The "Hurricane Season That Wasn't" officially ended on December 1, 2009, after a summer and fall marked by just seven named storms, two hurricanes, and no U.S. hurricane landfalls. The Post and Courier in Charleston covered the story ("Season uneventful, but experts say stay tuned," by Bo Petersen), as did USA Today ("Hurricane season ends with little bluster," by Oren Dorell).
Only two named storms made landfall on the U.S. coast in 2009: Tropical Storms Claudette and Ida, which passed over the Alabama and Louisiana coastline packing just 40-mph to 45-mph winds." Public Domain Image Courtesy Wikimedia Commons Weather scientists say an El Nino pattern in the Pacific was the biggest factor in the quiet season. Characterized by warm water in parts of the Pacific Ocean, along with low atmospheric pressure over the Pacific, El Nino tends to draw the North American jet stream air current southward, and creates high-level winds over the South Atlantic that disrupt hurricane formation. Colorado State University researchers, who issue a yearly hurricane forecast, amended their December 2008 prediction downward twice in early summer 2009, as the El Nino pattern strengthened and the jet stream effect became apparent. In a November 19, year-end summary, the Colorado State team said, "The skill of our early June and early August forecasts was reasonably good, while our earlier predictions of early December 2008 and early April of this year over-estimated this year’s tropical cyclone activity because of our inability to judge the formation of the moderate El Nin~o event, which began to develop late this spring." Last December, the team was calling for 14 named Atlantic storms in 2009; only 9 named storms occurred. The forecasters predicted 7 hurricanes; by season's end, there had been only 3. Instead of a predicted total of 70 days of named storm activity, this year the weather supplied only 27 storm days. In a detailed analysis of the season, the Colorado State team presents this litany of tropical calm: "The 2009 hurricane season had the following special characteristics:
- A late-starting season. Ana did not form until August 15. This was the latest ‘A’ storm of the season since Andrew formed in 1992 on August 17.
- Nine named storms occurred during 2009. This is the fewest named storms in a tropical cyclone season since 1997 when eight named storms formed.
- 27.25 named storm days occurred in 2009. This is the fewest named storm days since 1991, when only 24.25 named storm days were recorded.
- Three hurricanes occurred in 2009. This is the fewest hurricanes in a tropical cyclone since 1997 when there were also three hurricanes.
- Five named storms (Ana, Danny, Erika, Fred, and Henri) dissipated over the open ocean in the tropical and sub-tropical Atlantic this year. This is a fairly rare occurrence that typically only occurs in years such as this year that are characterized by high levels of tropospheric vertical wind shear.
- 11.25 hurricane days occurred in 2009. This is the fewest hurricane days since 2002 when 10.75 hurricane days were reported."
The slow season is sparking some discussion about the relationship between hurricane frequency, storm intensity, and global warming. Atlantic hurricanes represent only a fraction of the global tropical storm count — often, a slow Atlantic season may be more than outweighed by a busy Pacific storm season. But Florida State University graduate student Ryan Maue, who is analyzing global storm season history, says that the total storm energy of the Atlantic and Pacific climate zones combined is at historic lows — the rise in global temperatures notwithstanding. Blogs Maue: "Both Northern Hemisphere and South Hemisphere and therefore overall global hurricane activity has continued to sink to levels not seen since the 1970s. Even more astounding, when the Southern Hemisphere hurricane data is analyzed to create a global value, we see that Global Hurricane Energy has sunk to 30-year lows…." On the other hand, experts point out, the greatest risk factor for people isn't the storm frequency or intensity — it's the increasing flow of population and construction to the coastlines. Even Tropical Storm Ida, with its relatively weak winds, did a considerable amount of damage as the storm season came to an end. Crossing the Southeast U.S. from the Gulf of Mexico to the Atlantic, Ida re-formed as a strong nor'easter storm off the mid-Atlantic coast. Unlike hurricanes, which are intense but short-lived, nor'easters tend to hang around and pummel the coast for days — and that's what Ida did. From North Carolina to New Jersey and Long Island, Ida caused significant amounts of beach erosion and damage to structures. This Flickr photostream offers several good looks at the damage on the North Carolina Outer Banks. YouTube users "Frenchcald" took a video walk through some of the same Outer Banks territory, and offers this look at the nor'easter's destruction. So while the slow hurricane season represents a breather for coastal residents, it wasn't a free pass. As for next year, it's far too soon to say — but that has not stopped Colorado State's team from pointing out that the odds of an El Nino event continuing for two full years are very small. On December 9, the researchers released their look ahead at the 2010 season, saying, "We estimate that activity will return to levels more typical of years during an active era, such as what we have experienced since 1995... Because we are predicting an above-average hurricane season in 2010, the probability of U.S. and Caribbean major hurricane landfall is estimated to be above the long-period average."
