- Bomb cyclones form via rapid atmospheric pressure drops, defined as bombogenesis.
- Winter Storm Gianna is tracking across the Southeast, expected to bring significant snowfall.
- Eastern North Carolina could see peak snowfall amounts nearing 12 inches or more.
- States of emergency declared in North Carolina, South Carolina and Georgia for severe weather.
- Airlines are issuing travel alerts for nearly 50 airports amid storm concerns.
Millions in the Southeast are bracing for another winter storm set to arrive this weekend, with meteorologists warning the system is developing into a “bomb cyclone.”
So what is a bomb cyclone?
A bomb cyclone is a midlatitude winter storm that undergoes “bombogenesis,” a process where atmospheric pressure plummets at least 24 millibars in 24 hours. Millibars are a way of measuring pressure. The rapid drop indicates a storm is strengthening at a rapid pace, according to the National Oceanic and Atmospheric Administration.
“This can happen when a cold air mass collides with a warm air mass, such as air over warm ocean waters,” the organization shared.
While these storms share characteristics with hurricanes, including high winds, they are not the same. Hurricanes are fueled by warm air and typically form in tropical waters during late summer. However, bomb cyclones require cold air to thrive and develop between late fall and early spring.
What can the East Coast expect?
The storm, dubbed Winter Storm Gianna, is developing Friday across the southern United States. While the Gulf Coast, Florida Peninsula and the southern Atlantic coast will see scattered rain, inland areas like Mississippi, Alabama, Tennessee, Georgia and the Carolinas are expected to see snow or a mixture of rain and heavy snow, according to AccuWeather.
By Saturday morning, the system is expected to stretch across Georgia and the Carolinas, turning primarily to snow. Coastal regions face tropical-storm-force winds and giant waves, which the National Weather Service warns could trigger significant flooding and beach erosion.
Brian Hurley, a meteorologist at the Weather Prediction Center, said the Carolinas, especially eastern North Carolina and southeastern Virginia, can expect to see the highest amounts of snowfall, according to The New York Times.
“For example, in Elizabeth City, N.C. — a nice little town — the forecast is for 12.3 inches right now,” he said. He later highlighted that it would be in the top five depths recorded in the area.
North Carolina, South Carolina and Georgia are issuing states of emergency ahead of the extreme winter weather, according to ABC News. Gov. Brian Kemp of Georgia declared a statewide emergency Friday morning, authorizing the activation of the State Operations Center.
Power outages, poor travel conditions and life-threatening cold could last for days after the main body of the storm moves away, The Weather Channel warns.
Due to the bomb cyclone incoming, multiple alerts are in place for parts of the Southeast, as well as Cape Cod, Martha’s Vineyard and Nantucket Island, Massachusetts, according to The Weather Channel.
How will the latest storm affect travel?
While travel cancellations aren’t expected to be nearly as disruptive as last weekend during Winter Storm Fern, which grounded more than 10,000 flights, U.S. airlines are still taking precautions, as previously reported by the Deseret News.
American Airlines issued a travel alert for almost 30 airports across the Southeast. Delta Air Lines also issued a notice for travelers flying into or out of over 20 airports in the Southeast on Saturday or Sunday, according to Travel Pulse.