clone ▁to ▁form ▁and ▁do ▁not ▁always ▁rotate . ▁As ▁the ▁wall ▁cloud ▁desc ends , ▁a ▁fun nel - sh aped ▁cloud ▁may ▁form ▁at ▁its ▁center . ▁This ▁is ▁the ▁first ▁stage ▁of ▁torn ado ▁formation . ▁The ▁presence ▁of ▁a ▁mes ocy clone ▁is ▁believed ▁to ▁be ▁a ▁key ▁factor ▁in ▁the ▁formation ▁of ▁the ▁strong ▁torn ado es ▁associated ▁with ▁severe ▁th under st orm s . ▁ ▁T orn ado es ▁▁ ▁T orn ado es ▁exist ▁on ▁the ▁micro scale ▁or ▁low ▁end ▁of ▁the ▁mes osc ale ▁g amma ▁domain . ▁The ▁cycle ▁begins ▁when ▁a ▁strong ▁th under st orm ▁develop s ▁a ▁rot ating ▁mes ocy clone ▁a ▁few ▁miles ▁up ▁in ▁the ▁atmosphere , ▁becoming ▁a ▁super cell . ▁As ▁ra inf all ▁in ▁the ▁storm ▁increases , ▁it ▁drag s ▁with ▁it ▁an ▁area ▁of ▁quickly ▁desc ending ▁air ▁known ▁as ▁the ▁rear ▁fl ank ▁dow nd raft ▁( R FD ). ▁This ▁dow nd raft ▁acceler ates ▁as ▁it ▁approaches ▁the ▁ground , ▁and ▁drag s ▁the ▁rot ating ▁mes ocy clone ▁towards ▁the ▁ground ▁with ▁it . ▁ ▁As ▁the ▁mes ocy clone ▁approaches ▁the ▁ground , ▁a ▁visible ▁cond ens ation ▁fun nel ▁appears ▁to ▁descend ▁from ▁the ▁base ▁of ▁the ▁storm , ▁often ▁from ▁a ▁rot ating ▁wall ▁cloud . ▁As ▁the ▁fun nel ▁desc ends , ▁the ▁R FD ▁also ▁reaches ▁the ▁ground , ▁creating ▁a ▁g ust ▁front ▁that ▁can ▁cause ▁damage ▁a ▁good ▁distance ▁from