Ontario cold snap sparks 'exploding tree' warnings but experts say not to worry

As an icy polar vortex settles over Ontario, meteorologists are preparing for some of the coldest temperatures of the season yet, along with another major winter storm on Sunday.

Temperatures in the GTA are expected to plunge into the -20s on Friday night into Saturday morning, while areas north and northeast of the region will see conditions in the -30s.

Along with the extreme cold, a significant U.S. storm is expected to graze southern Ontario on Sunday, with the GTA possibly getting 20 to 30 centimetres of snow, which The Weather Network says is "certainly not out of the question."

Environment and Climate Change Canada has already issued a yellow cold warning for Toronto, noting that wind chill values will be near -30 to -33 degrees C on Friday evening into Saturday morning. If you're spending any time outdoors, the agency advises watching out for symptoms of cold-related illness, including shortness of breath, chest pain, numbness, and colour change in fingers and toes.

The upcoming deep freeze has led meteorologists and newscasters across Canada and the U.S. to take to social media with a term that sounds much scarier than it actually is: exploding trees.

Although it sounds pretty dramatic (and it certainly can be for the tree), experts stress that the phenomenon, which has been used quite frequently amid the deep freeze, doesn't actually resemble an action movie-style explosion.

Exploding trees coming soon to the frozen tundra near you. 🌬🥶 pic.twitter.com/GE8zT1yoaI

— ✨️Kristen✨️ (@_kAe_lEe_) January 22, 2026

Despite its name, which is more of a social media buzzword than an actual phrase experts use, affected trees don't just spontaneously combust into flames. Instead, there's a loud, sharp crack that may startle you if you're nearby.

According to the National Forest Foundation, there are several historic and current observations of trees cracking due to extreme cold.

I went camping in the woods in Ontario about 5 years ago in -40° weather and while falling asleep in my tent I could hear the sound of trees in the woods around me snapping and exploding. It was a pretty eerie sound. https://t.co/eesCm8CzTm

— Simon 🏕️ (@IHearSimon) January 21, 2026

This rare phenomenon involves the sap inside trees, which has a high water content, so when temperatures plummet fast enough for it to freeze, it expands. Under the right circumstances, the internal pressure becomes strong enough to tear open the bark and create a sudden rupture known as "frost crack."

According to The Weather Network, most native plants can handle cold temperatures, but if conditions cool outside of what's considered normal for the season, or if temperatures drop too quickly before a tree has time to acclimatize, this phenomenon can occur.

"Exploding Trees" are Possible in the Midwest. No, they don't actually explode but the expected extreme temperature drops can cause sap inside trees to freeze rapidly. This causes pressure to build causing a sudden fracture called a "Frost Crack". pic.twitter.com/jJG2NGyKl6

— Ben Olson (@radiobenolson) January 22, 2026

Experts maintain that the sound resembles a "gunshot" or a really "loud crack" as opposed to an actual explosion that would send wood flying through the air.

If you're out in nature this weekend in southern Ontario, you might hear a rare cracking sound echo through the woods. The phenomenon is far more startling than dangerous, and in reality, the extreme cold poses a much greater risk than the trees themselves.