Science & Tech · Science & Environment · 5 hrs ago
Polar vortex breaks down unusually early, adding uncertainty to winter forecasts
On Nov.
10, the polar vortex weakened and its winds reversed, marking its earliest recorded breakdown since weather balloon records began in the 1950s.
The vortex is a band of high-altitude winds around the Arctic that usually helps keep the coldest air near the North Pole.
When it weakens, Arctic cold can move south, potentially bringing colder or snowier weather to parts of Europe and North America in the coming weeks.
The event comes during an exceptionally strong El Niño, a warming of Pacific Ocean waters that often affects weather around the world.
Some scientists suspect El Niño helped weaken the vortex, while others say a high-pressure system over Scandinavia may have played a bigger role; the cause is not established.
El Niño often points to milder winters in much of North America, so the vortex disruption makes Canada’s winter outlook less predictable.
Forecasters say the vortex may start recovering within a week, but weather models suggest colder air and snow could reach parts of Canada later in November or early December.
The polar vortex weakened and its winds reversed on November 10, marking the earliest recorded breakdown of this kind.
The event could make winter forecasts less certain across Canada, the United States and Europe.
Scientists disagree about whether the record-strength El Niño caused or contributed to the breakdown.
A blocking high-pressure system over Scandinavia is another possible cause.
The disruption could bring colder air and snow in the coming weeks, but its effects and location remain uncertain.
- Who
- Scientists and meteorologists are assessing the polar vortex breakdown and its possible effects.
- What
- The polar vortex weakened and its winds reversed in an unusually early breakdown, adding uncertainty to winter forecasts.
- When
- November 10, 2026.
- Where
- The breakdown occurred in the stratosphere above the North Pole; possible weather effects could reach parts of Canada, the United States and Europe.
- Why
- Its cause is uncertain; a strong El Niño and a blocking high-pressure system over Scandinavia are possible contributors.
Supporters of an El Niño influence
Skeptics of an El Niño cause
Cause
Supporters of an El Niño influence
Adam Scaife suspects El Niño had some influence, though he says this is not proven.
Skeptics of an El Niño cause
Andrew Charlton-Perez says the Scandinavian blocking high is probably more important and cautions against attributing the event to El Niño.
The polar vortex weakened and its winds reversed, in the earliest recorded breakdown of this kind.
Meteorologists predict the polar vortex could begin recovering as stratospheric winds strengthen.
Some computer models begin to show snow and colder air.
- Breakdown date
- November 10, 2026
- Previous record
- The event was two weeks earlier than the previous record, according to Global News.
- Pacific temperature
- 3.5 C above average, according to Global News.
- Possible Canadian cold spell
- Some computer models show colder air and snow at the end of November and early December.
4 sources
What people are saying
There probably is some kind of El Niño influence on it
I would be wary of saying it was caused by El Niño
I guess the big question is, are these two separate occurrences, these two records happening all at once, or is there some sort of a correlation? And then as a meteorologist, what does that mean?
Some of our computer models are now starting to bring in some snow and some colder air at the end of November and early December so I think there’s going to be a lot of back and forth coming