800px-Occluded_mesocyclone_tornado5_-_NOAA bw.jpg
Caption:
Occluded mesocyclone tornado. Occluded means old circulation on a storm; this tornado was forming while the new circulation was beginning to form the tornadoes which preceeded the F5 Oklahoma City tornado, 1999
Credit:
OAR/ERL/National Severe Storms Laboratory (NSSL)
Sustainable development theme:
Country / location:
Anadarko, Oklahoma, USA