One of the big insults in the weather world is that droughts do not get included in the ranks of severe weather. I know why drought gets left out—the term "severe weather" is used to harbor the calamities that occur when rip-roaring thunderstorm systems leave their mark in the form of tornadoes, lightning, hurricane-force winds or hail.
Drought damage occurs over a long period of time. But talk to any farmer and I think you'll find he fears drought as much as any storm-related disaster. We all know why: Drought can kill a crop and ruin a farmer's balance sheet all in just one season.
Growers in the Southeast would, I think, agree drought is pretty darn severe—especially after the body blow dealt by the drought of 2007.
Climatologists called it a once-in-every-50-years occurrence. That may not be long enough for some folks!
From June on, rainfall struggled to even reach 50% of normal totals for the year at many stations.
By the end of harvest, soil moisture totals looked like figures from the desert: Alabama topsoil was 84% short to very short; Georgia, 72%; South Carolina, 59%; and Tennessee, 43%.
Some areas recorded the worst soil moisture to date in the 21st century, and most rainfall totals were more than 20 inches below average since Jan. 1.
With this kind of moisture deficit, many municipalities are rationing water. And of course, crop production slumped by as much as 20%.
BLAME LA NIÑA. What caused this round of parched conditions? Blame it on La Niña—the term given to describe cooler-than-average sea surface temperatures in the Pacific Ocean off the South American coast along the equator.
La Niña slowly developed during the summer. As this below-average tendency intensified, so did one of its hallmarks—a general lack of moisture in the atmosphere.
Not only did La Niña in general result in a dialing-back of moisture flowing into the southern U.S., but it also helped to strengthen the seasonal high-pressure system off the southeast U.S. coast known as the Bermuda High. That basically put the brakes on tropical storm activity moving into the southern U.S.
We're certainly feeling that lack of moisture now. Unfortunately, this problem isn't likely to improve much through early spring. We look for La Niña to be a moderate to strong feature well into April and May. That doesn't provide much chance for winter precipitation to improve the water table.
This drought problem in the Southeast isn't just getting the attention of folks there. Midwest farmers are also keenly aware of the prospects for this dryness to creep northward later in 2008.
A cataloging of major Corn Belt droughts by Iowa State University Extension climatologist Elwynn Taylor points out 16 of the past 17 drought seasons in the Corn Belt were preceded by droughts in the Southeast the previous crop year. That's a strong correlation.
And consider it's only about 500 miles from Atlanta, Ga., to southern Illinois—a pretty short distance when you're talking about a significant climate happening.
So, throughout much of 2008, the Southeast drought, La Niña and the correlation between the two will command headlines. And if and when it starts raining in Atlanta, Birmingham or Chattanooga, you'll probably hear shouts of "Hooray!" as far away as Des Moines.