How an intense snowstorm can match the ferocity of a thunderstorm
Some snowstorms are so intense that they can bury a town in a matter of hours. Here’s a look at how those memorable storms pump out so much snow in a hurry
Snowstorms are a dime a dozen across Canada during the winter months. But some of these systems are so intense that they’re remembered for generations.
Every once and a while, we’ll see a powerhouse of a storm that produces snowfall rates of 5-10+ cm per hour. Here’s a look at the vigorous snow bands that make for these memorable storms.
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A prolific snowstorm walloped southern Ontario in early 2022 with more than 50 cm of accumulation. Snowfall rates reached 10 cm per hour in some communities, an event that brought traffic to a standstill and disrupted everyday life throughout the region.
Southern Ontario found itself beneath a part of that historic storm known as a deformation zone, a feature that gives a healthy low-pressure system its classic ‘comma head’ appearance on satellite imagery.
Winds don’t blow around a low-pressure system in a perfect circle. These rushing winds constantly crash into the calmer air outside of the storm.
A deformation zone forms when upper-level winds spiralling around the centre of low pressure slow down and spread out as they hit the environment outside the storm.
This stretching motion creates a void in the upper atmosphere that air from the surface has to rush upward to fill.
Such intense lift mimics the updrafts in strong thunderstorms or lake-effect snow squalls, leading to the formation of very heavy bands of snow—usually on the northern or western side of a low-pressure system.
We can even get significant amounts of thundersnow from these ripping bands of convective snow.
This process is how nor’easters and coastal storms sometimes manage to pump out tremendous accumulations as they roar up the eastern seaboard.
Folks across Nova Scotia and Newfoundland are no strangers to intense snowfall rates as the northwestern side of a coastal low zips through the region. A mighty nor’easter dropped 40 cm of snow in St. John’s, Nfld., in February 2025.
One particularly intense example of enhanced banding in a snowstorm occurred over parts of the eastern U.S. on Feb. 16-17, 2024. Widespread snowfall totals of 5-15 cm fell throughout the Mid-Atlantic states that night.
A radar image of heavy snow over Pennsylvania and New Jersey on February 17, 2024. (NOAA)
However, a narrow band of intense snow developed over eastern Pennsylvania and New Jersey, where snowfall rates of 10+ cm per hour brought more than 35 cm of accumulation to some communities.
The cutoff was so sharp that Brooklyn, New York, measured 25 cm of snow while Central Park—just a few kilometres away—saw only about 8 cm of snow from the system.