Hurricane season off to a slow start

2013 compared to 2012 Storm Tracks Show caption
2013 compared to 2012 Storm Tracks

For a hurricane season that was forecast to be busy, this year’s has been blissfully quiet thus far.

Only six weather systems grew strong enough to get a name — and few of those kept their names for long. By this time last year, the count was up to 12 named storms, including the slow-moving Hurricane Isaac, which dragged across Louisiana for days and caused widespread flooding in several parishes.

In their Aug. 8 hurricane season update, National Oceanic and Atmospheric Administration scientists called for an above-average season with 13 to 19 named storms. Of those, six to nine were forecast to become hurricanes, and three to five of those were predicted to become major hurricanes with winds in excess of 110 mph.

The 30-year average for hurricane seasons is 12 named storms, six hurricanes and three major hurricanes per season.

Although this season has started quietly, the NOAA forecast could still prove correct.

August through the second week of October is the height of hurricane season, and weather conditions can change quickly.

“It’s not completely unusual to be a little behind like this,” said Ken Graham, the meteorologist in charge of the National Weather Service office in Slidell.

In 2010, there were only six named storms by Aug. 30 but the season had 19 by the time it ended in November.

And it takes only one storm to create widespread damage.

In 1992, there were only six tropical storms and one subtropical storm the entire season. But one of those storms was Hurricane Andrew, which caused billions of dollars in damage in Florida and Louisiana.

This year, none of the six named storms reached hurricane strength.

While a lack of hurricanes before Sept. 1 is not unheard of, it is unusual, said Barry Keim, Louisiana’s state climatologist.

“The last time we made it all the way through August without a hurricane was 2002,” Keim said.

In fact, in the past 161 years of record keeping, only 25 years were hurricane-free through the end of August.

“We’re definitely not complaining,” Keim added.

One reason for this year’s low number is the prevalence of upper atmospheric winds called wind shear, which has kept some storm systems from forming and others from growing stronger, Graham said. Also, the air over the Atlantic Ocean has been very dry this summer, starving storm systems of the moisture needed to strengthen.

“Dry air is the death of a tropical cyclone,” Graham said. “It basically evaporates. They just disappear.”

Finally, winds over the deserts of Africa have spewed a lot of dust into the air — another factor that dampens the formation of tropical storms.

“We’ve had a couple of things in the Gulf. They try and try and try, but they just can’t get going,” Graham said.

Keim noted that storms are indeed forming off the coast of Africa, but “they get pushed into this hostile area and they get ripped apart.”

One of the storms this year, Tropical Storm Andrea, hit Florida but brought primarily rain.

“It was seen as very welcomed when it came because it dumped a lot of rain in places that needed drought relief,” Keim said.

Though nothing indicates the weather conditions that have contributed to the quiet start of the season are going to change, long-term forecasts become more unreliable the further out they look.

“Bottom line is: things can change fast,” Keim said.

For emergency managers, the break from tropical storms is welcome but stirs fear that people will let their guard down. Mike Steele, spokesman for the Governor’s Office of Homeland Security and Emergency Preparedness, stresses that the hurricane season is still relatively young.

“September is still a very active time, historically, in Louisiana,” Steele said. “With the right kind of conditions, any storm can be dangerous.”