A strong stratospheric warming event is underway over the Arctic in early February 2026, rapidly weakening the Northern Hemisphere polar vortex. Forecasts indicate stratospheric westerly wind reversal and vortex split around mid-February, with cores separating further later.
A series of multi-vehicle collisions involving about 50 vehicles shut down sections of Highway 401 in eastern Ontario, Canada, on the morning of January 27, 2026, according to the Ontario Provincial Police. The crashes occurred near Trenton in Quinte West, forcing a full closure of the highway in both directions as emergency crews responded.
A powerful winter storm delivered record-breaking snowfall across Toronto, Ontario, Canada, on January 25, 2026, with 46 cm (18.1 inches) measured at Toronto Pearson International Airport as of 05:00 LT on January 26. This marks the highest single-day snowfall recorded since observations at the airport began in 1937. The event established new daily and monthly records for the site and caused widespread disruption across the Greater Toronto Area.
Meteorological forecasts show a major sudden stratospheric warming event forming over the Arctic, likely to cause significant weakening of the polar vortex in early February 2026. The resulting atmospheric disruption may alter jet-stream dynamics and increase the risk of Arctic air intrusions into North America and northern Europe during the second half of February.
A major polar vortex disruption has begun and is forecast to send Arctic air into much of North America and Europe through mid and late January 2026. The event will bring freezing temperatures and winter weather as the vortex weakens following a stratospheric warming episode. A second, stronger outbreak is forecast to occur during the last part of January as the core of the vortex splits into two halves, each driving cold Arctic air into Europe and North America in February.
One snowmobiler was killed by an avalanche on the Rockies Mountains in British Columbia on December 30, 2025.
A powerful bomb cyclone is forecast to strike Ontario bringing heavy snow, freezing rain, and severe winds from Sunday through Tuesday, December 28 to 30, 2025, as the deepening low crosses the Great Lakes. Environment and Climate Change Canada has issued Winter Storm and Freezing Rain Warnings, with snowfall totals of up to 50 cm (20 inches) and gusts exceeding 100 km/h (62 mph) expected in some areas.
Forecast models indicate that the Polar Vortex will strengthen in late December 2025 after a split and disrupted phase earlier in the season. The recovery is expected to influence North American and European weather in January 2026, potentially sending colder air southward while reorganizing jet stream flow.
The Center for Western Weather and Water Extremes (CW3E) at UC San Diego forecasts above-normal precipitation for Northern and Central California between late December 2025 and early January 2026. The latest subseasonal outlook, issued on December 16, indicates high confidence in enhanced atmospheric river (AR) activity and persistent Pacific Ridge conditions during the period from December 22 to January 11, 2026.
A powerful windstorm left over 120 000 customers, an estimated 300 000 people, without power on Wednesday, December 17, 2025, after winds of up to 90 km/h (56 mph) hit parts of the Lower Mainland.
