Key Takeaways:
- Severe cold temperatures can cause frost cracks in trees, but it’s rare for a tree to fully explode due to this phenomenon.
- Frost cracks are longitudinal cracks that can run the full length of a tree and are accompanied by a loud "bang".
- The temperature typically needs to drop to minus 20 degrees or lower for trees to begin cracking.
- Frost cracks are most likely to occur in thin-barked trees like maples, lindens, and sycamores.
- An arctic front is expected to bring frigid temperatures to the middle and eastern part of the country from January 22 through January 26.
Introduction to Frost Cracks
The recent severe cold temperatures hitting much of the country have led to warnings on social media about the possibility of "exploding trees". However, experts say that this is not entirely true. According to Bill McNee, a forest health specialist with the Wisconsin Department of Natural Resources (DNR), a sudden drop in temperature can cause a break in a tree known as a frost crack. 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.
What are Frost Cracks?
Frost cracks are vertical openings that can extend deep into the wood of a tree. They are most often found on the trunk, but branches can also be affected. McNee explained that 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 is when temperatures drop suddenly, causing the exterior of a tree to get much colder than a tree’s inner wood, leading to "unequal contraction" between the tissues of the tree’s exterior and interior.
Causes and Effects of Frost Cracks
Frost cracks are most likely to occur in thin-barked trees like maples, lindens, and sycamores, but can happen in other species as well. McNee said that 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. For most trees that do get a crack, the living part of the tree typically heals over the "wound" over time. However, a crack can expose a tree to fungal infection or decay, which could lead to the tree dying.
Other Strange Weather Phenomena
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. 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. 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.
Forecast and Precautions
An arctic front is expected to bring frigid temperatures to the middle and eastern part of the country from January 22 through January 26. Wind chills could fall as low as minus 60 across Illinois, Minnesota, and North and South Dakota. 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. 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, and it’s essential to take precautions to ensure public safety.
Conclusion
In conclusion, while the idea of "exploding trees" may seem alarming, it’s essential to understand that frost cracks are a natural phenomenon that can occur in trees during severe cold temperatures. By understanding the causes and effects of frost cracks, we can take necessary precautions to ensure public safety and protect our trees from potential damage. As the arctic front brings frigid temperatures to the country, it’s crucial to be aware of the potential risks and take steps to mitigate them.
