A building is severely damaged on US 98 East near Columbia, Miss., after a tornado touched down Tuesday, Dec. 23, 2014. According to Marion County Emergency Management the tornado touched down around 2:30 p.m. (AP Photo/The Hattiesburg American, Eli Baylis)

Severe storms slam the South, killing at least 4

Mississippi Gov. Phil Bryant declared an emergency Tuesday night for Jones and Marion counties where the deaths and injuries occurred. Officials say thousands remain without power Wednesday.

This June 17, 2013 photo, made available courtesy Sean Waugh, NOAA, shows graduate research assistant Kevin Rauhauser, with the University of Colorado's Research and Engineering Center for Unmanned Vehicles, (RECUV), launching the Tempest unmanned aerial vehicle for a test flight on Table Mountain, near Boulder, Colo. Researchers say they’ve collected promising weather data by flying instrument-laden drones into big storms, and now they want to expand the project in hopes of learning how tornados form.(AP Photo/Sean Waugh, NOAA)

Q&A: Drones might help show how tornadoes form

Drones can penetrate parts of weather systems that other instruments can’t reach, and they can do it at less cost and with less danger than piloted planes, according to scientists.