WOODBURY - The severe summer storms that slammed Long Island yesterday afternoon have prompted the closure of more than a dozen Nassau County beaches. The Nassau County Department of Health says storm runoff from yesterday's heavy rain has caused bacteria levels to spike in the water. The beaches affected are all along the North Shore, where the storms hit the hardest. The beaches that are closed to bathers are: Centre Island SoundCreek ClubLattingtown BeachLaurel Hollow BeachMorgan SoundNorth Hempstead Beach ParkPiping Rock Beach ClubPrybil BeachRansom BeachRoosevelt BeachSea Cliff Village BeachSoundside BeachStehli BeachTappen Beach