Podcast Episode
This sudden stratospheric warming event was only the second November occurrence documented since the 1950s, making the 2025-2026 winter season unprecedented in the satellite era.
The latest forecasts show another major stratospheric warming event unfolding in early February, with ensemble data indicating the vortex is splitting into two cores, a classic signal of full vortex collapse.
The synchronisation of this stratospheric collapse with a weak La Nina phase has created what meteorologists describe as a volatile atmospheric state that challenges traditional seasonal forecasting models.
Polar Vortex Collapse Unleashes Historic Arctic Blast Across Northern Hemisphere
February 5, 2026
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A rare polar vortex disruption that began in late November 2025 continues to drive extreme winter weather across North America and Europe. Meteorologists warn that February 2026 will see continued waves of Arctic air, with temperatures dropping thirty degrees Fahrenheit below normal in some regions.
Unprecedented Stratospheric Event
The polar vortex, a massive circulation of cold air that normally remains locked over the Arctic, has suffered one of the most significant collapses in recorded history. The disruption began around Thanksgiving 2025 when temperatures in the mid-stratosphere, approximately thirty kilometres above Earth's surface, spiked by thirty to fifty degrees Celsius within just a few days.This sudden stratospheric warming event was only the second November occurrence documented since the 1950s, making the 2025-2026 winter season unprecedented in the satellite era.
How It Works
Under normal conditions, the polar vortex acts as a giant atmospheric lid, keeping frigid Arctic air contained near the North Pole. When sudden stratospheric warming occurs, the circumpolar winds that maintain this boundary slow down and can even reverse direction, effectively breaking the seal on the Arctic cold reservoir.The latest forecasts show another major stratospheric warming event unfolding in early February, with ensemble data indicating the vortex is splitting into two cores, a classic signal of full vortex collapse.
Widespread Impacts
For the eastern United States, temperatures are expected to remain four to ten degrees Fahrenheit or more below historical averages through at least mid-February, with the Midwest experiencing the greatest departures from normal. Europe faces similar conditions, with a blocking high over Greenland allowing cold northerly flow to penetrate the continent.The synchronisation of this stratospheric collapse with a weak La Nina phase has created what meteorologists describe as a volatile atmospheric state that challenges traditional seasonal forecasting models.
What Comes Next
Once the polar vortex is disrupted, recovery can take a month or longer. Current forecasts suggest the cold pattern may extend into early spring, with the possibility of additional weather disruptions as the weakened vortex continues allowing Arctic air to escape southward.Published February 5, 2026 at 9:15am
