A bomb cyclone occurs when the atmospheric pressure drops so quickly that the weather system increases rapidly in strength and brings high winds. The pressure has to drop at least 24 millibars in 24 hours to create a bomb cyclone and the storm can cause costal flooding and blizzard like conditions during the winter. The storm, Grayson, blew the standard by dropping 59 millibars during the first 24 hours.
Boston, Massachusetts had already experienced massive flooding where parts of the Boston Harbor overflowed with chucks of ice. Roads in Massachusetts were turned into slushy rivers