Because the atmosphere hates pressure differences, these high winds whipping over a low pressure system create something like a hole in a doughnut: Warm air starts to rise rapidly through the center of the storm to even things out, but this causes the pressure at the center of the storm to plummet. Bombogenesis, the calling card of a bomb cyclone, happens when the barometric pressure at the center of the cyclone pressure drops at least 24 millibars in 24 hours (a millibar is a unit of measurement for atmospheric pressure). Some of these storms can intensify much more quickly, though, dropping 60 millibars in 24 hours.
The result, as you can imagine, is impressive. These storms can be as intense as a regular-season hurricane, but even more ferocious as they can drop immense amounts of snow as well as 50 mile per hour (80.5 kilometer per hour) winds, causing flooding, beach erosion, loss of power and storm surges.