Bomb Cyclone 2021 Map: Which States Have Been Affected?

The West Coast of the U.S. has been subject to some pretty harsh weather conditions over the past few days, all thanks to the bomb cyclone—a weather event which has caused everything from mudslides to powercuts in some states.

The cyclone, which takes place when winds become suddenly more intense due to a quick drop in atmospheric pressure, has been battering the western part of the country, bringing with it heavy rainfall and incredible high wind speeds.

Newsweek breaks down where in the U.S. has been affected by the bomb cyclone.

Which States Have Been Affected By the Bomb Cyclone?

Initially, the bomb cyclone was focused in the north west of the country, affecting Washington, Oregon and, after heading further south, California.

However, when it arrived on Sunday, October 24, other areas were also battered by high winds.

According to CNN, there were 13 reports of tornadoes in Missouri, Illinois and Kansas.

On Monday, October 25, thousands of Californians were left without electricity due to the force of the event.

According to the National Weather Service (NWS), up to 10 inches of rain was expected to fall on the West Coast over the course of that day, and the Bay Area in San Francisco was left flooded.

Northeast of San Francisco, which was been affected by wildfires prior to the cyclone's arrival, has also suffered mudslides due to the burn scars on the land.

These burn scars make the ground less stable, meaning heavy rain can dislodge gravel, stones and mud which subsequently flow downhill.

Later that day, the NWS maps suggested the storm was making the move across the country, with even New York at risk of heavy rain.

A thunderstorm warning was put in effect on Monday evening for Maryland, Virginia and North Carolina. Flash flood warnings were later put in place from Massachusetts to New Jersey until late on Tuesday, October 26.

TODAY: Scattered severe thunderstorms associated with large hail, wind damage and isolated tornadoes are expected across portions of KS, OK, and northern/central TX late this afternoon through the evening into the overnight.

Find your local NWS office at

— National Weather Service (@NWS) October 26, 2021

Currently, warnings of storms and tornadoes are in place around Texas, Kansas and Oklahoma.

What Is a Bomb Cyclone?

Speaking to Newsweek, AccuWeather meteorologist Nicole LoBiondo said a bomb cyclone is "a rapidly strengthening storm with a central pressure that plummets by 0.71 of an inch of mercury (24 millibars) or more within 24 hours. The process is referred to as bombogenesis."

LoBiondo said that due to the long drought experienced in the West, this cyclone brought with it much-needed rainfall, though still came with dangers.

Before the storm hit, she said: "The powerful storm will bring dangerous and damaging impacts up and down the West Coast, but the precipitation it will deliver to parts of California, Oregon and Washington is greatly needed. As the storm comes together a few hundred miles off the coasts of Washington and British Columbia, its intensification could easily surpass the criteria for bombogenesis."

The time to be most vigilant, LoBiondo said, was from Sunday to Tuesday, however she also warned that while there seemed to be a break in the storm pattern, by next weekend another cyclone could impact the region.

As a result, those living in flood-prone areas should take heed of warnings from the NWS.

Bomb cyclone effects
Heavy waves break against the Oregon coast as a bomb cyclone storm system moves over the Northwest United States on October 24, 2021 in Depoe Bay, Oregon. Heavy rain and wind may cause flooding in some parts of the region. Nathan Howard/Getty Images