Winter weather tips for staying warm and safe
When it’s freezing outside, a DIY warming compress or changing the direction of your ceiling fan can make all the difference.
Severe cold temperatures hitting much of the country this week could branch out − literally.
As people brace for the winter weather, some social media posts in recent days have warned of the chance for exploding trees.
But experts say that’s not entirely true.
A sudden drop in temperature can cause a break in a tree known as a frost crack, Bill McNee, a forest health specialist with the Wisconsin Department of Natural Resources (DNR), told the Milwaukee Journal Sentinel, part of the USA TODAY Network.
While frost cracks can be loud and cause branches to fall off, it would be extremely rare for a tree to fully explode because of it, McNee said.
Here’s what we know about “exploding” trees.
Can severe weather really cause exploding trees?
McNee said it’s not uncommon for a sudden drop in temperature to cause “frost cracks” in trees. These longitudinal cracks can run the full length of a tree and are accompanied by a loud “bang,” according to the Wisconsin DNR.
“It’s going to get cold enough that this sap may actually finally freeze. And when it does that, like ice cubes in your freezer, they expand very quickly,” McNee told the Journal Sentinel. “That just creates a lot of physical pressure that can lead to the frost cracking appearing suddenly, branches can fall off, and people hear this really loud crack from their tree, almost like it’s a gunshot.”
It would be unlikely for a tree to fully explode due to frost cracking; usually, the crack becomes part of the tree, McNee said.
“I’ve never seen the damage of it, but from what I have seen and what I read online is that it is rare for there just to be so much pressure that is suddenly released inside this tree that it almost does explode,” McNee said.
McNee advised anyone who sees a severe crack in a tree to consult an arborist to evaluate if the tree is a safety hazard. Severe frost cracking could cause trees to fall.
What are frost cracks? ‘Exploding tree’ phenomenon
Frost cracks are vertical openings that can extend deep into the wood of a tree. They are most often on the trunk, but branches can also be effected, according to the University of Connecticut.
McNee said frost cracks occur because the thick sap inside a tree freezes at a colder temperature than water, and usually stays liquid even when temperatures are well below freezing – a state known as “supercooling.”
Another factor that can lead to frost cracks, according to the Wisconsin DNR, is that when temperatures drop suddenly, the exterior of a tree can get much colder than a tree’s inner wood, causing the cells of the tree’s bark to shrink and lead to “unequal contraction” between the tissues of the tree’s exterior and interior.
Frost cracks are most likely to occur in thin-barked trees like maples, lindens and sycamores, but can happen in other species, according to the DNR. McNee said any tree that has sap could have frost cracking in the right conditions.
Frost cracking is common for many trees every few winters, and some trees adapt by dehydrating themselves before winter, making it less likely for physical damage to occur, McNee said. For most trees that do get a crack, the living part of the tree typically heals over the “wound” over time, he said. However, a crack can expose a tree to fungal infection or decay, which could lead to the tree dying.
Other strange weather effects: Thundersnow, pancake ice
So-called exploding trees aren’t the only strange weather phenomena out there.
Thundersnow, a rare weather event, occurs when snow, rather than rain, accompanies a thunderstorm.
Pancake ice, a type of ice that resembles the breakfast staple, forms in bodies of water in cold weather when waves are still churning the surface. Chunks of ice collide and clump together, forming round, flat disks that resemble pancakes floating on the water’s surface, according to The Weather Channel.
Snow rollers, a kind of nature-made snowball, are a cylindrical forming of snow that happens when snow chunks roll down hills or are blown along the ground by wind, according to the Idaho State Department of Education.
And when it comes to cracks, another phenomenon known as a frost quake or cryoseism can create cracks in the ground caused by the freezing and expansion of water deep within the earth’s crust, according to AccuWeather.
Forecast: Severe cold is on the way
An arctic front is expected to bring frigid temperatures to the middle and eastern part of the country from Jan. 22 through Jan. 26, according to the National Weather Service’s latest forecast.
Wind chills could fall as low as minus 60 across Illinois, Minnesota and North and South Dakota. From the northeast to states as far west as Colorado and Montana, wind chills are expected to hover around 10 degrees below zero. In the southern half of the country, from New Mexico to South Carolina, wind chills could be around 10-20 degrees.
Meanwhile, a winter storm will bring heavy snow from the Southern Rockies and Plains through the Mid-Atlantic and into the Northeast through the weekend, per the NWS.
Melina Khan is a national trending reporter for USA TODAY. She can be reached at [email protected].
This story was updated because an earlier version included an inaccuracy.
