A severe winter storm is sweeping through the United States' eastern seaboard on Thursday. Footage from New York City shows blowing snow and strong wind gusts taking hold of the city. Snow flurries will likely carry through to Thursday evening. The entire East Coast is bracing itself for hurricane-force gales and sub-zero temperatures overnight. A 'bomb cyclone', which developed overnight... Еще, occurs when a system goes through a significant, rapid drop in atmospheric pressure.