Why is this winter storm likely to be a land storm?

most The United States is preparing For a long period of time Cold weather And a Huge winter storm Which could cause chaos on roads and electricity networks over the next few days.

at least 170 million Americans are under winter weather alerts. “Extremely cold temperatures and dangerously cold winds” will continue even after the storm ends, dumping heavy snow, sleet and freezing rain across the southern Rockies all the way into New England through Monday. The National Weather Service (NWS) warned. Friday. Meteorologists expect the low temperatures to break several records, with chills reaching minus 50 degrees Fahrenheit in the northern Plains.

It’s been a little It is difficult for forecasters to get a good idea ahead of time Where will this storm go and who will be most affected? They’re driven by complex factors that scientists are still working to better understand, starting with frigid Arctic air on a collision course with a weather system moving inland from the moisture-packed Pacific Ocean.

“It doesn’t look like a normal winter storm,” says Andrea Lopez-Lange, an associate professor and atmospheric scientist at the University of Wisconsin-Madison. The effects can be particularly long-lasting. With such a large area of ​​the United States affected, there will likely be a wide range of impacts from place to place. “Make sure you pay attention to your local expectations, because the effects can be quite different, even though this is all part of the same system,” Lopez-Lang advises.

Parts of the Arctic are covered in darkness for months at a time during the winter, allowing the air to become constantly colder. Normally, a stream of strong winds called the jet stream prevents Arctic air from significantly affecting temperatures further south. But the large high-pressure system allowed the jet stream to decline, allowing very cold air to reach Canada and the United States.

When a moisture-packed weather system moves from the Pacific Ocean far enough inland to collide with the jet stream, the mix of wet and cold conditions can create a cascade of dangers from snow and freezing rain. The latter, which occurs when raindrops freeze when they strike a surface, allows ice to accumulate on roads and infrastructure. Persistent cold after a storm prolongs the danger.

“The storm will cause large and locally catastrophic ice accumulations with the potential for prolonged power outages, widespread tree damage, and extremely hazardous or impassable travel conditions,” NWS said. He says in his predictions. The ice is heavy and can down power lines and leave some homes without power or heat in the event of a power outage. The deadly cold snap in Texas in 2021 has left Millions of homes are without heat After gas pipes become clogged with ice.

It is too early to say what role climate change may play in this particular storm. However, there were unique triggers to this storm, which may have been influenced by climate change. First, the atmosphere can hold more water vapor, which can It leads to heavy rain With storm systems.

The jet stream has happened too More ridiculous. Historically, the difference in temperature between the tropics and the poles has made it relatively constant. But the Arctic is warming faster than the rest of the planet. As the temperature difference becomes less pronounced, the jet stream bends more, allowing Arctic air to push southward as the jet stream meanders.

It’s already getting severe cold spells like this Less common With global temperatures rising. Experts say this could pose its own challenges because communities may not be prepared to deal with them when they arrive Edge. They stress that it is important to understand that climate change can affect extreme events of all kinds, not just heat.

“People say, ‘Oh, well, it’s too cold or we’re getting too much snow — how is the world warming?’” Climate change is an increase in core temperatures, but it’s also an increase in extreme temperatures in both directions, says Caitlin Trudeau, a senior research associate at the nonprofit Climate Central. “It can lead to very cold outcomes; “It could lead to more extreme warming outcomes… Judging climate change by a cold storm is like judging a baseball season by one inning.”

Lopez-Lang is bracing for the impact of the storm in Wisconsin, both on her home and her business. Weather permitting, she and her colleagues plan to fly into the storm as it makes its way off the East Coast to study how it develops. They will be on board NASA’s aircraft to make measurements of water vapor, temperature and other factors affecting the event. They want it Study storm structure To better understand what happens when a weather system like the one causing problems this week meets the jet stream.

After all, some of the initial questions about how this week’s storm will unfold stem from forecasters trying to figure out when and how this merger will occur. “These mergers are big components of forecast uncertainty,” Lopez-Lange says. “So we want to make sure we monitor it well so we can get the best data to make the best predictions.”