Yes , and unsurprisingly they do that . Now , this is anecdotal and unsourced , but the pilots I know who do this have told me that for the $ 10 M it costs in a summer it saves about $ 500 M in payouts . Also , the silver iodide not lead is released from flares , just like the ones used in roadside emergencies . So 20 of those get released over 50100 miles , and only while inside a storm , where they ' ll pretty much instantly be used as a nucleation site for condensation after all , this is the whole point . Were talking a tiny , tiny amount of stuff . Anything which did make it out of the storm is in a layer of atmosphere known for its 100 knot winds , so dispersal will be thorough . Honestly man , you ' re looking for a Boogeyman that isn ' t there .