(MCT) — WASHINGTON — Hurricane Sandy seems straight out of the latest Hollywood apocalyptic blockbuster. But a confluence of environmental and topographical characteristics helps explain its vast size, slow progress, storm surge and multiple methods of wreaking havoc on the coast and deep inland, scientists say.

Sandy began as a big storm when it came together in the Caribbean, said Katie Garrett, a meteorologist with the National Weather Service. It grew even larger as it moved north and into the mid-Atlantic, fed by unseasonably warm waters.