Meteorologists sometimes warn of a winter storm that could “bomb out” or become a bomb cyclone. According to the US National Oceanic and Atmospheric Administration, this happens when a storm's central pressure drops at least 24 millibars in 24 hours. The lower the pressure, the stronger the storm. These rapidly strengthening storms can produce heavy rain and intense winds, creating dangerous conditions. Bomb cyclones mainly occur in fall and winter when Arctic air clashes with warmer air masses. Regions prone to these storms include Alaska, the Pacific Northwest, and the Great Lakes.