How the polar vortex and warm ocean intensified a major US winter storm

Mathew Barlow, UMass Lowell and Judah Cohen, Massachusetts Institute of Technology (MIT)

A severe winter storm that brought crippling freezing rain, sleet and snow to a large part of the U.S. in late January 2026 left a mess in states from New Mexico to New England. Hundreds of thousands of people lost power across the South as ice pulled down tree branches and power lines, more than a foot of snow fell in parts of the Midwest and Northeast, and many states faced bitter cold that was expected to linger for days.

The sudden blast may have come as a shock to many Americans after a mostly mild start to winter, but that warmth may have partly contributed to the ferocity of the storm.

As atmospheric and climate scientists, we conduct research that aims to improve understanding of extreme weather, including what makes it more or less likely to occur and how climate change might or might not play a role.

To understand what Americans are experiencing with this winter blast, we need to look more than 20 miles above the surface of Earth, to the stratospheric polar vortex.

What creates a severe winter storm like this?

Multiple weather factors have to come together to produce such a large and severe storm.

Winter storms typically develop where there are sharp temperature contrasts near the surface and a southward dip in the jet stream, the narrow band of fast-moving air that steers weather systems. If there is a substantial source of moisture, the storms can produce heavy rain or snow.

In late January, a strong Arctic air mass from the north was creating the temperature contrast with warmer air from the south. Multiple disturbances within the jet stream were acting together to create favorable conditions for precipitation, and the storm system was able to pull moisture from the very warm Gulf of Mexico.

Where does the polar vortex come in?

The fastest winds of the jet stream occur just below the top of the troposphere, which is the lowest level of the atmosphere and ends about seven miles above Earth’s surface. Weather systems are capped at the top of the troposphere, because the atmosphere above it becomes very stable.

The stratosphere is the next layer up, from about seven miles to about 30 miles. While the stratosphere extends high above weather systems, it can still interact with them through atmospheric waves that move up and down in the atmosphere. These waves are similar to the waves in the jet stream that cause it to dip southward, but they move vertically instead of horizontally.

You’ve probably heard the term “polar vortex” used when an area of cold Arctic air moves far enough southward to influence the United States. That term describes air circulating around the pole, but it can refer to two different circulations, one in the troposphere and one in the stratosphere.

The Northern Hemisphere stratospheric polar vortex is a belt of fast-moving air circulating around the North Pole. It is like a second jet stream, high above the one you may be familiar with from weather graphics, and usually less wavy and closer to the pole.

Sometimes the stratospheric polar vortex can stretch southward over the United States. When that happens, it creates ideal conditions for the up-and-down movement of waves that connect the stratosphere with severe winter weather at the surface.

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The forecast for the January storm showed a close overlap between the southward stretch of the stratospheric polar vortex and the jet stream over the U.S., indicating perfect conditions for cold and snow.

The biggest swings in the jet stream are associated with the most energy. Under the right conditions, that energy can bounce off the polar vortex back down into the troposphere, exaggerating the north-south swings of the jet stream across North America and making severe winter weather more likely.

This is what was happening in late January 2026 in the central and eastern U.S.

If the climate is warming, why are we still getting severe winter storms?

Earth is unequivocally warming as human activities release greenhouse gas emissions that trap heat in the atmosphere, and snow amounts are decreasing overall. But that does not mean severe winter weather will never happen again.

Some research suggests that even in a warming environment, cold events, while occurring less frequently, may still remain relatively severe in some locations.

One factor may be increasing disruptions to the stratospheric polar vortex, which appear to be linked to the rapid warming of the Arctic with climate change.

Additionally, a warmer ocean leads to more evaporation, and because a warmer atmosphere can hold more moisture, that means more moisture is available for storms. The process of moisture condensing into rain or snow produces energy for storms as well. However, warming can also reduce the strength of storms by reducing temperature contrasts.

The opposing effects make it complicated to assess the potential change to average storm strength. However, intense events do not necessarily change in the same way as average events. On balance, it appears that the most intense winter storms may be becoming more intense.

A warmer environment also increases the likelihood that precipitation that would have fallen as snow in previous winters may now be more likely to fall as sleet and freezing rain.

There are still many questions

Scientists are constantly improving the ability to predict and respond to these severe weather events, but there are many questions still to answer.

Much of the data and research in the field relies on a foundation of work by federal employees, including government labs like the National Center for Atmospheric Research, known as NCAR, which has been targeted by the Trump administration for funding cuts. These scientists help develop the crucial models, measuring instruments and data that scientists and forecasters everywhere depend on.

This article, originally published Jan. 24, 2026, has been updated with details from the weekend storm.

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Mathew Barlow, Professor of Climate Science, UMass Lowell and Judah Cohen, Climate scientist, Massachusetts Institute of Technology (MIT)

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The science section of our news blog STM Daily News provides readers with captivating and up-to-date information on the latest scientific discoveries, breakthroughs, and innovations across various fields. We offer engaging and accessible content, ensuring that readers with different levels of scientific knowledge can stay informed. Whether it’s exploring advancements in medicine, astronomy, technology, or environmental sciences, our science section strives to shed light on the intriguing world of scientific exploration and its profound impact on our daily lives. From thought-provoking articles to informative interviews with experts in the field, STM Daily News Science offers a harmonious blend of factual reporting, analysis, and exploration, making it a go-to source for science enthusiasts and curious minds alike. https://stmdailynews.com/category/science/

How City Hall Quietly Undermined LA’s Own Height Limits

The Knowledge Series | STM Daily News

For more than half a century, Los Angeles enforced one of the strictest building height limits in the United States. Beginning in 1905, most buildings were capped at 150 feet, shaping a city that grew outward rather than upward.

The goal was clear: avoid the congestion, shadows, and fire dangers associated with dense Eastern cities. Los Angeles sold itself as open, sunlit, and horizontal — a place where growth spread across land, not into the sky.

And yet, in 1928, Los Angeles City Hall rose to 454 feet, towering over the city like a contradiction in concrete.

It wasn’t built to spark a commercial skyscraper boom.
But it ended up proving that Los Angeles could safely build one.

A Rule Designed to Prevent a Manhattan-Style City

The original height restriction was rooted in early 20th-century fears:

• Limited firefighting capabilities
• Concerns over blocked sunlight and airflow
• Anxiety about congestion and overcrowding
• A strong desire not to resemble New York or Chicago

Los Angeles wanted prosperity — just not vertical density.

The height cap reinforced a development model where:

• Office districts stayed low-rise
• Growth moved outward
• Automobiles became essential
• Downtown never consolidated into a dense core

This philosophy held firm even as other American cities raced upward.

Why City Hall Was Never Meant to Change the Rules

City Hall was intentionally exempt from the height limit because the law applied primarily to private commercial buildings, not civic monuments.

But city leaders were explicit about one thing:
City Hall was not a precedent.

It was designed to:

• Serve as a symbolic seat of government
• Stand alone as a civic landmark
• Represent stability, authority, and modern governance
• Avoid competing with private office buildings

In effect, Los Angeles wanted a skyline icon — without a skyline.

Innovation Hidden in Plain Sight

What made City Hall truly significant wasn’t just its height — it was how it was built.

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At a time when seismic science was still developing, City Hall incorporated advanced structural ideas for its era:

• A steel-frame skeleton designed for flexibility
• Reinforced concrete shear walls for lateral strength
• A tapered tower to reduce wind and seismic stress
• Thick structural cores that distributed force instead of resisting it rigidly

These choices weren’t about aesthetics — they were about survival.

The Earthquake That Changed the Conversation

In 1933, the Long Beach earthquake struck Southern California, causing widespread damage and reshaping building codes statewide.

Los Angeles City Hall survived with minimal structural damage.

This moment quietly reshaped the debate:

• A tall building had endured a major earthquake
• Structural engineering had proven effective
• Height alone was no longer the enemy — poor design was

City Hall didn’t just survive — it validated a new approach to vertical construction in seismic regions.

Proof Without Permission

Despite this success, Los Angeles did not rush to repeal its height limits.

Cultural resistance to density remained strong, and developers continued to build outward rather than upward. But the technical argument had already been settled.

City Hall stood as living proof that:

• High-rise buildings could be engineered safely in Los Angeles
• Earthquakes were a challenge, not a barrier
• Fire, structural, and seismic risks could be managed

The height restriction was no longer about safety — it was about philosophy.

The Ironic Legacy

When Los Angeles finally lifted its height limit in 1957, the city did not suddenly erupt into skyscrapers. The habit of building outward was already deeply entrenched.

The result:

• A skyline that arrived decades late
• Uneven density across the region
• Multiple business centers instead of one core
• Housing and transit challenges baked into the city’s growth pattern

City Hall never triggered a skyscraper boom — but it quietly made one possible.

Why This Still Matters

Today, Los Angeles continues to wrestle with:

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• Housing shortages
• Transit-oriented development debates
• Height and zoning battles near rail corridors
• Resistance to density in a growing city

These debates didn’t begin recently.

They trace back to a single contradiction: a city that banned tall buildings — while proving they could be built safely all along.

Los Angeles City Hall wasn’t just a monument.
It was a test case — and it passed.

Further Reading & Sources

• Los Angeles Department of City Planning – History of Urban Planning in LA
• Los Angeles Conservancy – History & Architecture of LA City Hall
• Water and Power Associates – Early Los Angeles Buildings & Height Limits
• USGS – How Buildings Are Designed to Withstand Earthquakes
• Los Angeles Department of Building and Safety – Building Code History

More from The Knowledge Series on STM Daily News

Blue Origin has officially kicked off its 2026 flight calendar, successfully completing the 38th mission of its New Shepard program and further solidifying its role in commercial human spaceflight.

The suborbital flight, known as NS-38, carried six private astronauts beyond the Kármán line, offering several minutes of weightlessness and sweeping views of Earth before a safe return to West Texas. The mission marks the first New Shepard launch of 2026 and another milestone for Blue Origin’s reusable spaceflight system.

Metro Transit Update: Sepulveda Corridor & C Line South Bay Recap – STM Daily News Podcast

The NS-38 Crew

The six-person crew aboard NS-38 included:

• Tim Drexler
• Dr. Linda Edwards
• Alain Fernandez
• Alberto Gutiérrez
• Jim Hendren
• Dr. Laura Stiles

With this flight, New Shepard has now flown 98 humans into space, representing 92 individual passengers. The growing total reflects Blue Origin’s emphasis on routine, repeatable access to space—once considered experimental, now becoming operational.

A Reliable Start to 2026

Blue Origin leadership emphasized reliability and customer trust as central priorities moving into the new year.

“As we enter 2026, we’re focused on continuing to deliver transformational experiences for our customers through the proven capability and reliability of New Shepard,” said Phil Joyce, Senior Vice President of New Shepard. “We are grateful for our astronaut customers who put their trust in our team to bring this experience into reality.”

The fully reusable New Shepard rocket and capsule system has demonstrated strong safety performance, autonomous operations, and consistent recovery—key elements in scaling human spaceflight.

Building Toward a Larger Vision

Beyond space tourism, New Shepard plays a foundational role in Blue Origin’s long-term goal of enabling millions of people to live and work in space for the benefit of Earth.

As the company’s first operational human spaceflight system, New Shepard supports:

• Reusable launch vehicle testing
• Human-rated safety system validation
• Increased launch cadence and manufacturing expertise
• Future Blue Origin programs and missions

Each successful flight expands operational confidence while helping normalize commercial access to space.

What’s Next for Aspiring Astronauts

Blue Origin continues to accept interest from future New Shepard passengers, with additional flights expected throughout 2026. The company also released commemorative merchandise from the NS-38 mission, now available through the Blue Origin Shop.

As commercial spaceflight matures, missions like NS-38 highlight the industry’s shift from novelty to normalcy—bringing space closer to scientists, explorers, and private citizens alike.

Related Articles & Information

• Blue Origin – New Shepard Program Overview
  Official overview of Blue Origin’s reusable suborbital rocket and human spaceflight system.
• Blue Origin – Human Spaceflight Missions
  Details on past and upcoming crewed New Shepard missions.
• NASA: Humans in Space
  NASA’s overview of human spaceflight history and current programs.
• Commercial Spaceflight: How Private Companies Are Changing Access to Space
  STM Daily News coverage of the growing space tourism and commercial launch industry.
• Reusable Rockets Explained: Why They Matter
  An explainer on reusable rocket technology and its impact on space exploration.

For more updates, insights, and in-depth coverage of space exploration and commercial spaceflight, visit the STM Daily News blog at stmdailynews.com. From mission breakdowns to industry trends and technology explainers, STM Daily News keeps you informed about humanity’s journey beyond Earth.

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