A car drives down a snowy main street in downtown Juneau, Alaska, on Dec. 29, 2025. Becky Bohrer/AP Photo

When turbulent weather with whipping winds and heavy snow is in the forecast, meteorologists sometimes warn that a storm could “bomb out” or become a bomb cyclone. But what exactly does this mean?

According to the U.S. National Oceanic and Atmospheric Administration, certain storms undergo bombogenesis, which happens when a storm’s central pressure drops at least 24 millibars in 24 hours. These storms are sometimes called bomb cyclones. Storm intensity is measured by central pressure, so the lower the pressure, the stronger the storm.

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