TULSA, Oklahoma - In what would normally be the heart of tornado season, we seem to be experiencing a "tornado drought."

And the lull comes just two years after one of the most active and deadly severe weather seasons in history.

May is normally the most active month for severe weather, but so far this month, the National Weather Service says there have only been three confirmed tornadoes across the nation.

Back in 2011, that number was over 300.

"The cold weather and the fact that we just had sleet and snow in the last week, really disrupts the spring storm cycle," said NWS Meteorologist Steve Piltz.

Piltz said the late snow isn't just affecting Oklahomans, but it's the entire nation, as well.

"We should be somewhere around 150 to 160 reports. Right now, we're at about 80-something," Piltz said. "If you had to pick a six-week window where you're really concerned that a town could really get run over by a bad storm, it would be now, but its just not happening."

So far, only three people across the country have been killed by tornadoes in 2013.

Two years ago it was a different story. There were more than 500 deaths at this point back in 2011.

"Really, in just a couple-year swing, we've seen the worst Mother Nature can do during severe weather, and now were seeing some of the calmer severe weather seasons," Piltz said.

News On 6 Meteorologist Mike Grogan said, "We're dealing with an event that, statistically speaking, should only happen once every 28,000 years."

Grogan said a recent study shows our current tornado drought is actually more uncommon than the outbreaks we saw two years ago. He said moisture in the Gulf of Mexico that normally fuels tornadoes is being pushed down by cold air coming from the north.

It's been 21 days since a tornado warning has been issued in Green Country.

"I saw other weather offices that hadn't issued warnings, at all, for the previous several months, and that's highly unusual," Grogan said.

But despite the lull of tornadoes this year, Oklahomans should still be ready for severe weather.

"Tornado season can turn on like a light switch," Grogan said. "All it takes are a couple big tornado outbreaks to completely reverse the story of this year with tornadoes."