Bomb cyclone drops historic amount of snow on Southeast

The winter storm that has dropped over a foot of snow on parts of North Carolina has officially hit bomb cyclone criteria off the Southeast coast as it continues to strengthen.

A bomb cyclone is a rapidly strengthening storm that undergoes a significant drop in pressure – one measure of a storm’s strength – in a short time.

A storm’s pressure must drop at least 24 millibars (a unit of pressure) in 24 hours or less to undergo bombogenesis or “bomb out” and meet the bomb cyclone criteria.

This storm’s pressure fell about 27 millibars in the 24 hours ending 1 a.m. ET. It’s still intensifying, so the pressure fall could become even bigger this morning.

Strong winds are whipping across parts of the Southeast because of the storm’s intensity, especially on the coast. Gusts over 50 mph have been recorded this morning from North Carolina’s Outer Banks to southeast Virginia.