BOULDER, COLO. (AP) -- Scientists have completed the first phase of a two-year, $12 million project to study tornadoes in the central U.S.

Members of Vortex2 encountered only one twister while stalking storms in a nine-state region -- including Texas -- with about 120 researchers and 50 vehicles.

The June 5 twister in southeastern Wyoming was isolated and moved in a relatively straight line.  Vortex2 stands for Verification of the Origins of Rotation in Tornadoes Experiment-2.  Vortex2 focused on Wyoming, Texas, Minnesota, South Dakota, Iowa, Nebraska, Colorado, Kansas and Oklahoma.

The project is mainly funded by the National Science Foundation and the National Oceanic and Atmospheric Administration.  The field study resumes in May.

(Copyright ©2009 by The Associated Press. All Rights Reserved.)