Wind vortex (7)
I believe the answer is:
tornado
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">wind vortex</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for tornado that I've seen before include "A violent and destructive whirlwind" , "Cyclone, twister" , "Violent whirlwind over land" , "Terrible storm" , "Severe wind" .)