Explanation given for uncommon weather event witnessed during snowstorm in Ontario

Southern Ontario experienced a major snowstorm on Friday night, with heavy snowfall. However, residents were surprised to witness thundersnow just before 9 p.m. During thundersnow, lightning and thunder occur together with a snowstorm. Although this is a rare phenomenon, according to CP24 meteorologist Chris Potter, it is not entirely uncommon.

Potter explained that certain mechanisms must be at play for thundersnow to occur, such as significant lift and convection.

Residents soon began to upload photos and videos of the phenomenon.

Several rounds of thundersnow being heard and seen on Lakeshore in Toronto. Somewhere beyond all that snow are the Toronto Islands and Lake Ontario! #ONStorm pic.twitter.com/FK3zJYUymF

— Daniel Milligan (@danielrmilligan) March 4, 2023

Lightning could be seen brightening the skies as snow poured down over the city.

Thundersnow in Kitchener #ONStorm pic.twitter.com/lNDtwi3nNm

— Marc Charette (@Marc_Charette) March 4, 2023

The phenomenon was also experienced in Kitchener, Ont., and as far as Michigan, U.S.

The Farmer’s Almanac explains that thunderstorms result from the violent overturning of an unstable air mass, usually caused by a significant difference in temperature. Thundersnow is uncommon because the colder lower layers of air during winter have a lower dew point, making it unusual for atmospheric clashes to occur during colder months. However, thundersnow does occur, especially in the Great Lakes region, where cold air over the milder Great Lakes rapidly forces the air upwards, leading to lightning and thunder alongside heavy snow.

CTV News Toronto weather specialist Jessica Smith notes that late winter storms are not uncommon as the battle between cold arctic air and warmer southern air intensifies during the transition to spring. These high-impact systems, known as Texas Lows, will have the greatest impact from 9 p.m. Friday through 12 a.m. Saturday, with heavy, wet snow expected to continue into Saturday morning.