storm. leslie not expected to hit the u.s. michael became the seventh hurricane of the season, but no threat to land. a relatively light year for tornados, but we have seen dozens of twisters in the past week alone. we have isaac to blame for that. abc's sam champion has more. >> reporter: remnants of hurricane isaac are dumping rain, 9 inches in the past 24 hours in new jersey. and spawning twisters. this is cell phone video of a funnel cloud forming in cherry hill, new jersey. isaac has been a tornadomaker since its landfall. this one, in gulf port, mississippi. and has left a trail of twisters for days as far north at arkansas, missouri, and illinois. but even with all of isaac's action, it has been a surprisingly light summer for tornadoes. the severe storms laboratory in norman, oklahoma now saying it is the quietest year since the 1950s. and this summer's crippling dome of heat and drought are the reason. no rain means no storms.