What is polar vortex? Major disruption expected across US and Canada – The Times of India

A powerful polar vortex collapse is forecast to hit within weeks, bringing a dramatic shift in weather conditions across the United States and Canada. Meteorologists predict the event will unfold in mid-March, marking the second major disruption of the polar vortex in 2025. The first collapse occurred in mid-February, unleashing a deep freeze across much of the central and eastern US.
Forecasters warn that this upcoming vortex disruption could be particularly intense, bringing extreme winter conditions even as the season draws to a close.
What is a Polar Vortex?
A polar vortex is a massive area of low pressure and frigid air that typically surrounds the Earth’s poles. It strengthens during winter and weakens in summer, but occasionally, disruptions in the jet stream cause it to shift, allowing Arctic air to plunge southward. The polar vortex exists in the stratosphere, with winds exceeding 155 mph in a stable state.
How will it impact the weather?
When the polar vortex remains strong, it contains cold air within the Arctic region, maintaining relatively stable weather patterns. However, when it weakens or collapses, the jet stream becomes unstable, allowing frigid Arctic air to spill into lower latitudes. This results in severe cold snaps, heavy snowfall, and unpredictable weather patterns.
The UK Met Office explains: “A stronger jet stream brings stormy and wet weather, while a weaker one allows more frequent outbreaks of Arctic air, leading to colder temperatures.”
What happens when the polar vortex collapses?
A polar vortex collapse, also known as a Sudden Stratospheric Warming (SSW) event, occurs when stratospheric temperatures rise rapidly—sometimes by as much as 50°C within days. This disturbance weakens the vortex, reversing its winds and allowing Arctic air to surge southward.
The Met Office explains: “As the cold air from the stratosphere sinks into the troposphere, it disturbs the jet stream, triggering dramatic weather shifts.”
As March approaches, forecasters will continue monitoring developments, but early warnings suggest the potential for another round of extreme winter conditions across North America. The coming weeks could see a sharp downturn in temperatures, reinforcing winter’s grip just as many hope for spring’s arrival.