La Crosse, Wisconsin – Residents across the Upper Mississippi Valley should be prepared for sudden loud cracks or booming sounds Friday as lingering Arctic cold renews the risk of the “exploding tree” phenomenon across the region.
According to the National Weather Service, deeply cold air remains in place Friday, with subzero temperatures and biting wind chills creating prime conditions for frost cracking, also known as cryoseismic booming. This happens when sap inside trees freezes rapidly and expands while the outer wood contracts, building pressure that can cause trunks to split abruptly with a sharp, explosive sound.
The highest risk Friday morning stretches along and near the Mississippi River, including southeastern Minnesota, western Wisconsin, and northeastern Iowa. Communities such as Rochester, Winona, Red Wing, La Crosse, Eau Claire, Prairie du Chien, and Dubuque are especially vulnerable, particularly in wooded river valleys and older neighborhoods with mature hardwood trees. Cracking is most likely during the coldest pre-dawn hours.
While exploding trees are uncommon, splitting trunks and falling limbs can damage vehicles, sidewalks, roofs, and power lines. Residents are advised to avoid standing beneath large trees during extreme cold and to park vehicles away from tree-lined streets when possible.
The same cold driving tree stress also increases the risk of frostbite on exposed skin within minutes, frozen pipes, and vehicle issues. Officials urge limiting outdoor exposure Friday, dressing in insulated layers, covering all exposed skin, and keeping pets indoors. Cold-related advisories remain in effect, with additional updates possible if conditions persist or intensify.
