What’s a bomb cyclone? Here’s what you need to know about the terrifying weather term

An intensifying storm on the Pacific Coast has been reported as a possible bomb cyclone approaching Washington state. The pressure system is expected to cause high winds and rain along the coast and in some parts of the state.

This is abnormal for this time of year, according to meteorologist Maddie Kristell with the National Weather Service in Seattle.

But what is the definition of a bomb cyclone, and how serious is it?

What is a bomb cyclone?

A bomb cyclone, also referred to as bombogenesis by meteorologists, occurs when a storm at a midlatitude is rapidly strengthened, according to Accuweather. It’s measured by the drop in pressure, generally achieving bombogenesis status if the storm drops 24 millibars of pressure in less than 24 hours, according to the National Oceanic and Atmospheric Administration. Midlatitude is the latitude between tropics and polar regions.

“Storms, of course, always have lower atmospheric pressure, but in this case the atmospheric pressure is lowering very quickly as the storm system intensifies,” stated AccuWeather Chief Meteorologist Jon Porter in an online article.

However, this general rule will vary by the latitude of the storm, according to NOAA.

How severe are bomb cyclones?

So what does this mean? How dangerous are these storms?

A storm’s expected impact will vary, based on its location, pressure rate and projected path. That said, bombogenesis can lead to some of the most violent weather systems affecting a broad area, according to Accuweather.

Storms are already low pressure systems, but the rate at which nearby air is pulled into the center of a storm increases with bomb cyclones due to the extreme pressure drop.

“As these winds move toward the center of the storm at high speed, property damage can occur, trees may fall and the power may go out,” notes the Accuweather article.

Bomb cyclone preparation in WA

It’s currently unconfirmed if the storm over the Pacific Ocean is officially a bomb cyclone, but the Weather Service anticipates high winds and snowfall around Washington. High wind watches have been posted for the coast and east Puget Sound lowland areas of the state, but we’re expected to miss the most severe impacts of the storm.

When experiencing such strong winds, there are certain protections you can take. Be mindful of your location. You’re better off in an interior room on the lowest floor of a sturdy building, and you should avoid cars and mobile homes, according to the National Weather Service.

Bomb cyclones can also cause precipitation at rapid rates, though that is not expected in Washington with this storm.

Do you have a question or story idea for the Northwest Service Team? Let us know here:

This story was originally published November 18, 2024 at 12:40 PM.