USA could see record quiet year for tornadoes

• Only 750 tornadoes reported so far this year
• An average year, to this date, would see about 1,200
• Weather pattern that led to drought prevented tornadoes from forming

Following on the heels of a deadly 2011, when almost 1,700 tornadoes killed 553 Americans, 2012 has been a remarkably quiet year for tornadoes across the USA.

"We may set an all-time record low for the year," says meteorologist Harold Brooks of the National Severe Storms Laboratory in Norman, Okla.

So far this year, about 750 tornadoes have been reported in the USA. At this time last year, about 1,500 had formed. An average year, to date, has about 1,200 tornadoes, says Greg Carbin, warning coordination meteorologist at the Storm Prediction Center in Norman.

"This points to how variable tornado counts are from one year to the next," Carbin adds.

"We'll have to be above normal the last three months of the year to not get a record," Brooks says. On average, about 143 tornadoes form from October-December in the USA, according to the National Climatic Data Center.

He says that since accurate tornado records began in the 1950s, the year with the fewest tornadoes was 1987, when only 1,013 tornadoes were reported.

The same weather pattern that created the devastating drought was a factor in the quiet tornado year, according to meteorologist Mike Smith of AccuWeather Enterprise Solutions in Wichita, Kan. He says that for much of the year, a large area of high pressure sat over the West Coast and the Rockies, which kept storms from moving into the central USA, the nation's tornado hotbed.

As the atmosphere shifts to an El Nino climate pattern this fall, he says, the storm track could shift and bring the chance for more tornadoes to the central U.S. El Nino is a periodic warming of tropical Pacific Ocean water that affects weather around the world.

Typically, there is a small uptick in tornadoes in late October and early November anyway, as the fall atmosphere is similar to the stormy spring season.

Tornadoes have killed 68 Americans so far, mostly in late February and early March. The worst outbreaks were on Feb. 28-29, when 15 people died, and on March 2, when 40 died, according to the Storm Prediction Center. Most of the deaths occurred in the Ohio Valley region.

"After a very busy start during the winter of 2012, tornado events dropped off markedly by late April," Carbin says. "May and June had some of the lowest counts on record, but the numbers are not quite final yet and the counts remain preliminary. The tornado drought, just like precipitation drought across much of the country, continues."