How Climate Change Supercharges Winter Storms

A massive, frigid storm is currently developing across the United States, stretching from the Southwest up into the Northeast. This system is putting much of the country in a deep freeze that will last until early next week.

The sheer scale of this weather event is staggering, with The Weather Channel warning that more than 230 million people could be impacted. As heavy snow and catastrophic ice accumulations blanket the region, the National Weather Service is predicting wind chills below -50 degrees Fahrenheit in the Northern Plains. This creates a dangerous situation for travel, power infrastructure, and vulnerable populations.

If it feels like you are standing at the North Pole right now, there is a scientific reason for that. High above the Arctic, a massive, very cold air mass known as the polar vortex is swirling. Typically, this frigid air is kept in place by a strong wind pattern called the jet stream, which acts as a barrier separating the Arctic from warmer air to the south.

However, that barrier is currently weakening. The jet stream has been meandering and becoming wobblier, allowing the polar vortex to break free and dip southward into the United States. This shift in atmospheric dynamics is what brings the extreme cold directly into the lower 48 states, creating the widespread freeze currently being experienced.

Why is the jet stream becoming less stable? Scientists point to Arctic amplification, a phenomenon where the Arctic is warming four times faster than the rest of the planet. As sea ice dwindles, darker waters are exposed, which absorb more of the sun's energy than reflective ice does. This creates a feedback loop of warming.

According to Ayumi Fujisaki-Manome, an earth scientist at the University of Michigan, this warming reduces the temperature contrast between the Arctic and the south. She explains,

"When that happens, the jet stream tends to meander a lot, and that allows very cold air to come down to the south."

This reduced temperature gradient is the primary suspect in making the jet stream wavier and more prone to these dramatic shifts.

While the cold air comes from the Arctic, the storm's power is being fueled by something much warmer: the oceans. The research group Climate Central notes that the waters of the Gulf of Mexico and the Pacific off Baja California are exceptionally warm right now. These record-high temperatures are made much more likely by humanity's carbon emissions.

This oceanic heat loads the atmosphere with extra moisture. When that moisture collides with the system swooping down from the Arctic, it supercharges the storm. As the atmosphere warms, its capacity to hold moisture increases, leading to heavier precipitation. This is why the current storm is producing not just cold, but also heavy snow and catastrophic ice accumulations across a massive swath of the country.

The connection between climate change and a wavier jet stream is a subject of active research and debate within the scientific community. Jacob Chalif, a researcher at Dartmouth College, notes the difficulty in proving a direct causal link.

"The problem is that it's really hard to show whether or not that's happening,"

Chalif said, pointing out that solid records of the jet stream only go back to 1979.

To overcome this limitation, Chalif led a study using machine learning to analyze climate records stretching back to 1901. The findings revealed that the jet stream was often wavy even before 1979, sometimes more so than today.

"In other words, the impact of climate change on the jet stream, I think, remains unclear,"

Chalif stated.

"I don't think we have a smoking gun that we're making the jet stream wavier yet."

Despite the debate over the jet stream's behavior, the influence of climate change on the storm's intensity is not in question. The warmer atmosphere and super-heated oceans are undeniable factors in the severity of the weather. As Kaitlyn Trudeau, a senior research associate for climate science at Climate Central, noted,

"Judging climate change by a cold storm is like judging a baseball season by a single inning. But, climate change has a tangible impact on this storm."

As the storm continues to unfold, bringing dangerous conditions to millions, it serves as a complex example of our changing climate. While the mechanics of the polar vortex and jet stream are intricate, the outcome is clear: a supercharged winter event affecting more than 230 million people.