Polar vortex collapse threatens North America with extreme cold in March

A new collapse of the polar vortex is forecast to strike North America in mid-March, bringing significant impacts to the weather across the United States and Canada. Meteorologists warn that this event, the second of 2025, could outstrip the intensity of February’s occurrence, despite the waning winter season. Tied to a Sudden Stratospheric Warming (SSW), the phenomenon promises to push Arctic air masses into lower latitudes, challenging infrastructure, transportation, and the daily lives of millions. Regions like the U.S. Midwest and Canadian provinces such as Ontario are already bracing for sharp temperature drops and extreme conditions. The forecast reignites discussions about climatic unpredictability in a month typically linked to the onset of spring.

The polar vortex, defined by a vast mass of cold air and low pressure encircling the poles, plays a critical role in regulating winter weather in the Northern Hemisphere. When stable, it keeps frigid air locked in the Arctic, aided by the polar jet stream, a high-altitude wind current. However, its disruption, as anticipated now, destabilizes this natural barrier, allowing cold to spill into areas like Chicago, New York, and Toronto. In February, the year’s first collapse showcased its might, delivering blizzards and sub-zero temperatures below -20°C in American cities. This time, the event’s strength could amplify effects, impacting a broader area and lingering for days or even weeks.

Interaction between the vortex and the jet stream drives these dramatic shifts. With stratospheric winds exceeding 155 mph facing interruptions, cold air escapes southward, turning March weather into an unexpected extension of winter. In the United States, the Northeast and Midwest are on alert, while Canada tracks provinces like Quebec and Manitoba. The mix of strong winds, snow, and low temperatures is set to test the resilience of cities and communities, underscoring vulnerability to such powerful atmospheric events.

Understanding the phenomenon and its effects

The polar vortex collapse is not an isolated incident but part of a complex atmospheric process influencing global weather. Situated about 30 kilometers above the surface in the stratosphere, the vortex is a dynamic structure that strengthens between November and March, weakening in summer due to seasonal temperature shifts. Its winds, spinning counterclockwise, form a barrier that, when intact, prevents Arctic air from reaching populated regions. Yet, a Sudden Stratospheric Warming can raise stratospheric temperatures by up to 50°C in days, disrupting this circulation and unleashing widespread cold waves.

Under normal conditions, the polar jet stream acts as a shield, keeping weather stable in mid-latitudes. When the vortex weakens, however, this current becomes wavy, allowing frigid air masses to reach unprepared areas. In the U.S., cities like Minneapolis faced extreme temperatures in February, while in Canada, Alberta logged heavy snowfalls. The March event, experts say, could intensify this pattern, with temperature drops of up to 15°C below average in places like New York and Toronto. The phenomenon’s unpredictability poses a planning challenge for authorities and residents alike.

Beyond temperatures, the collapse brings added risks like snowstorms and biting winds. These conditions directly affect daily life, from highway traffic to power grid reliability. In 2025, the recurrence of extreme events tied to the polar vortex raises questions about shifting weather patterns, demanding closer attention to changes in global atmospheric circulation.

Predicted impacts for March

North America is gearing up for a fresh климатический test with the looming polar vortex collapse. In the United States, the Midwest and Northeast, still reeling from February’s chill, sit at the forecast’s epicenter. Chicago, which saw snow buildup and icy winds earlier this year, may witness similar scenes again, while New York faces potential freezing rain as cold air meets Atlantic moisture. In Canada, provinces like Ontario and Quebec expect harsh wind chills, with gusts amplifying already low temperatures.

Expected effects include:

• Significant temperature drops, reaching as low as -20°C in cities like Minneapolis and Winnipeg.
• Snowstorms capable of disrupting highway traffic and airport operations.
• Power grid strain from heightened heating demand.
• Infrastructure risks, such as frozen pipes in homes and public buildings.

These impacts are poised to affect millions, particularly in densely populated urban areas. In February, over 150 million people in the U.S. felt the first collapse’s effects, with blizzards halting life in cities like Detroit and Boston. Now, with predictions of an even stronger event, the geographic scope and duration of the cold spark concern among officials closely monitoring the jet stream’s path.

In Canada, coastal regions like British Columbia may also see effects, though the interior and east remain the primary focus. The blend of Arctic air with moisture systems could produce heavy precipitation, including deep snow and ice, further complicating community responses. March’s shift toward typically milder weather makes this event especially disruptive, catching many off guard.

Timeline of 2025 events

The year 2025 has already logged a striking series of polar vortex collapses, highlighting its growing influence on North American weather. The first event, in mid-February, unleashed a cold wave that impacted vast swaths of the U.S. and Canada, delivering record lows and widespread disruptions. Now, the second collapse, slated for March, reinforces a pattern of consecutive atmospheric disturbances, a trend scientists are tracking to understand potential long-term climate shifts.

Here’s a timeline of events recorded so far:

• February 2025: Initial collapse releases Arctic air, affecting 150 million people in the U.S. and bringing blizzards to states like Ohio and Michigan.
• March 2025: Second collapse expected mid-month, with potential to hit a wider area and last longer.
• Ongoing monitoring: Scientific teams track stratospheric conditions to predict further disruptions before winter’s end.

The rapid succession of these phenomena underscores the vulnerability of regions unaccustomed to out-of-season cold snaps. Compared to prior years, 2025 stands out for the intensity and frequency of these ruptures, fueling discussions about the effects of global climate variations on polar vortex behavior.

Heightened preparations in affected regions

Facing the March climate threat, authorities and residents across North America are mobilizing to mitigate impacts. In the U.S., Midwest cities like Minneapolis and Chicago are stockpiling road salt and inspecting heating systems in public buildings. States like Wisconsin, hardened by February’s freeze, keep emergency crews on standby for power outages and heavy snow. In Canada, Ontario expands shelter capacity to protect vulnerable populations, while Manitoba ramps up hypothermia risk alerts.

Residents are also acting swiftly. In Toronto, demand for portable heaters has surged, and in New York, locals stock up on thermal blankets anticipating the worst. Local weather services issue steady guidance, urging precautions like pipe insulation and preparation for transportation disruptions. Businesses and schools weigh closures or remote operations, depending on worsening conditions—a step some took in February.

These preparations reflect lessons from the prior event, but March’s projected strength demands heightened vigilance. The unpredictability of weather in this transitional month underscores the need for coordinated responses, as millions track updates closely, aware of the polar vortex’s transformative potential.