Source: IE
Subject: Geography
Context: A polar vortex–driven winter storm swept across the United States in January 2026, bringing heavy snow, freezing rain and sub-zero temperatures to nearly 17 states, causing deaths and severe travel disruptions.
About Polar Vortex:
What it is?
- The polar vortex is a large, persistent area of low pressure and extremely cold air that circulates around the Earth’s polar regions.
- It exists in two forms:
- Tropospheric polar vortex (lower atmosphere, where weather occurs)
- Stratospheric polar vortex (higher atmosphere, strongest in winter)
How it forms?
- During winter, reduced solar heating at the poles creates intense cold air, generating a strong low-pressure system.
- This system drives fast-moving winds that normally keep Arctic air locked near the poles.
Factors influencing polar vortex disruptions:
- Jet stream behaviour: A strong vortex keeps the jet stream stable; a weakened vortex makes it wavy, allowing cold air to spill south.
- Sudden Stratospheric Warming (SSW): Rapid warming in the stratosphere can weaken or split the vortex.
- Arctic amplification: Faster warming of the Arctic compared to lower latitudes reduces the temperature gradient, making the vortex more unstable.
- Atmospheric pressure systems: Blocking high-pressure systems can divert cold air toward mid-latitudes.
Implications:
- Local impacts:
-
- Extreme cold waves, heavy snowfall, ice storms and wind chill hazards.
- Energy stress, power outages and disruption to transport and daily life.
- Increased risks of hypothermia and frostbite in regions unaccustomed to such cold.
- Global impacts:
-
- Cold surges in North America, Europe and Asia linked to polar vortex shifts.
- Greater weather volatility, with sharper contrasts between extreme cold spells and warmer periods.
- Raises concerns about how climate change may be reshaping atmospheric circulation, even as average global temperatures rise.
