A polar vortex collapse is expected to hit in mid-March, unleashing severe winter weather and major travel disruptions across the United States and Canada. The extreme cold may also extend its impact to the UK and Europe, heightening weather concerns across the region.
This will mark 2025’s second polar vortex collapse, following the previous occurrence which brought freezing conditions and transport difficulties across North America.
What is a polar vortex collapse?
A polar vortex is a vast zone of low pressure and frigid air that swirls around the Earth’s poles, acting as a key driver of winter weather patterns.
This system is closely linked to the jet stream, a fast-moving current of winds that flows between 8 to 11 kilometers above the Earth’s surface.
When the polar vortex weakens, it disrupts the stability of the jet stream, allowing icy Arctic air to surge southward. This intrusion of frigid air can trigger severe and unpredictable weather, leading to extreme cold snaps, heavy snowfall, and widespread disruptions.
How does a polar vortex collapse take place ?
A polar vortex collapse takes place when temperatures in the stratosphere, between 10 and 50 kilometers above Earth’s surface, rise sharply by up to 50 degrees within 48 hours—a phenomenon known as sudden stratospheric warming (SSW).
This abrupt warming disrupts the stability of the polar vortex, weakening its structure and allowing frigid Arctic air to spill southward. As a result, regions that typically experience milder winters can face extreme cold, heavy snowfall, and severe weather disruptions.
How, where and when will it impact?
February witnessed widespread snow, storms and below-freezing temperatures affecting numerous Americans across most of the nation. Should the forthcoming vortex disruption reduce jet stream strength, it could enable frigid air from polar regions to move into North America or Eurasia.
“We are predicting a displacement of the polar vortex on the Europe and eastern Canada side of the polar,” AccuWeather’s Lead Meteorologist Paul Pastelok told The Independent.
“When the polar vortex is disrupted – whether stretched, displaced, or split – it can, but does not always, impact this polar jet stream,” he continued.
“The timing is uncertain for North America but could see a change in the pattern for late March into early April,” he added.
The upcoming stratospheric occurrence appears to be more intense than its predecessor, potentially causing a reduction in jet stream intensity. Such conditions could facilitate polar air masses moving towards southern regions of North America or Eurasia, raising the possibility of substantial snowfall in certain areas.