The 100-plus researchers who set out earlier this year on the biggest scientific twister hunt in history have returned with few tornado tales to tell.

The VORTEX2 project (the Verification of Rotation in Tornadoes EXperiment 2) is a two-year, $10.5-million undertaking planned to study tornadoes in hopes of improving early warning systems.

But this first year of study turned out to be an unusually quiet one for twisters. In the first six months of the year, 826 tornadoes were recorded, according to an Associated Press report. That might sound like a ton—even to Dorothy and Toto types. But it’s a good gust fewer than the average for each of the past three years—which is 934—and a lot less than last year, in which 1,304 tornadoes had spun up by June 30.

“It was very, very unusual,” Joe Schaefer, director of the Storm Prediction Center in Norman, Okla., told the AP. In fact, in peak tornado season, more than two weeks went by without a single tornado warning going out in the U.S.

“You’re out there to do the experiment and you’re geared up every day and ready,” Don Burgess, of the University of Oklahoma, told the AP. “And when there isn’t anything happening, that is frustrating.”

Meteorologists attribute the sedate season to the spring and summer’s unusual jet stream pattern, which has been flowing more east-west across the nation’s midsection rather than the more common south-north direction. The change has also been blamed on other aberrant weather patterns, such as the severe drought in Texas and the Northeast’s cool, wet summer.

One big tornado did spin up over Wyoming in June, however, which gave the scientific storm chasers a good sample. And they will be back in the hunt late next winter to see if 2010 brings more wild weather their way.