"Bomb Cyclone" Brings Bitter Cold Weather To The US East Coast

The extreme hurricanes and devastating wildfires of 2017 caused $306 billion in total damage, making it the most expensive year on record for natural disasters in the United States. Unfortunately, 2018 has commenced with extreme weather conditions of its own. After a frigid last week of December, the East Coast of the United States is being pummeled with a “bomb cyclone” winter storm that has brought bitterly cold temperatures, deep snow, and hurricane-speed winds to the region.

Contrary to what the name might suggest, there is nothing explosive about what is being dubbed winter storm Grayson. “Bomb cyclones” get their name from the process that creates them: bombogenesis. Derived from the words “bomb" and "cyclogenesis" (a technical term for storm formation), they tend to occur in the winter due to the collision of warm and cold air masses.

The western North Atlantic is particularly susceptible to the phenomenon because the cold air over North America collides with warm air over the ocean, which tends to retain more heat. The drop in pressure creates a gap between the hot and cold air masses, leading to high winds that help fuel the storm. “When you have this really tight temperature gradient, you can get these pieces of energy — weather disturbances – coming through the atmosphere,” says meteorologist Ed Vallee.

For many areas, the storm has brought blizzard-like conditions not experienced for decades. In Boston, the strong winds resulted in the highest tides since 1978, leaving many streets surging with water. The city also received more than a foot of snow, and 20,000 people throughout Massachusetts have lost power. The mighty Niagara Falls is partly frozen, while the Atlantic Ocean’s usually rolling waves sport a thick crust of ice over its salty waters. Though common along the coast of Alaska, the phenomenon has rarely been seen in the lower 48 states. Saturday’s wind chill caused the Northeast’s highest peak, Mount Washington in New Hampshire, to feel as cold as -93 degrees Fahrenheit (-69 degrees Celsius) and tie with Armstrong, Ontario as the second coldest region in the world.

The southern states have not escaped Grayson’s fury either. Ordinarily mild areas like Georgia and South Carolina have experienced freezing rain that has made driving perilous, while residents of Tallahassee, Florida are learning to cope with the first snowfall in 30 years. The unusually frigid weather has caused the nearly-frozen iguanas in South Florida to fall out of trees. Luckily, the cold-blooded animals, which become immobile when the temperatures drop beyond a certain level, fully recover once they thaw out.

All in all, Grayson has affected 100 million people, grounded thousands of flights, caused numerous school districts to close, and severely impacted public transportation throughout the East Coast. So far, at least 22 people have perished from the cold. Fortunately, temperatures are expected to return to seasonable norms by the end of this week.

While many people have attributed Grayson to climate change, some meteorologists caution making that connection, as the event is not unusual. Between 40 and 50 “bomb cyclones” occur annually worldwide, but since most manifest over the open ocean, they are rarely noticed. However, other experts argue that as the ocean temperatures continue to rise, the wicked winter storms may become a common occurrence. Rutgers climatologist Jennifer Francis says, “We expect these patterns to become more frequent, but they may align differently in different years.”

Resources: livescience.com,nationalgeographic.com,accuweather.com,wired.com