Minneapolis, MN – As a surge of arctic air tightens its grip on Minnesota, residents from the Twin Cities north to Duluth may experience loud, sudden booms during the coldest overnight hours. State geologists and meteorologists say the noises are likely frost quakes, a little-known winter phenomenon triggered by rapid ground freezing.
What Are Frost Quakes?
Frost quakes, scientifically known as cryoseisms, occur when water-saturated soil freezes too quickly. Rainfall or melting snow seeps into the ground, and when temperatures plunge rapidly, that trapped moisture expands as it turns to ice. The pressure builds until the frozen ground suddenly cracks, releasing energy that can sound like an explosion or a thunderclap.
Unlike earthquakes, frost quakes are not caused by tectonic activity and do not register on seismic fault systems. However, their suddenness and volume can be startling, especially in quiet winter nights.
Why Minnesota Is at High Risk Right Now
Meteorologists say the current weather setup across Minnesota is nearly ideal for frost quakes. Several factors are coming together at once:
- Wet or saturated ground from recent precipitation
- Minimal snow cover, allowing cold air to penetrate the soil more deeply
- Rapid temperature drops, with conditions shifting from above freezing to well below zero in just hours
Forecasts indicate overnight lows could fall to –10°F in parts of central and northern Minnesota this week, including areas stretching from Minneapolis through Duluth.
When Frost Quakes Usually Happen
Frost quakes most commonly occur between midnight and early morning, when temperatures reach their lowest point. Residents often report hearing sharp cracks, booms, or rumbling noises that can:
- Shake windows
- Rattle walls
- Vibrate floors
- Startle pets and residents
In some cases, frost quakes may leave small surface cracks in pavement, minor fissures in frozen soil, or visible frost heaves in yards and driveways.
Are Frost Quakes Dangerous?
Experts emphasize that frost quakes are rarely dangerous. Structural damage to homes is uncommon, and injuries are extremely rare. However, the noises can be alarming, and minor ground movement may affect outdoor surfaces.
Geologists note that frost quakes tend to be more common in regions with clay-rich or water-retaining soils, which are widespread across Minnesota.
How Homeowners Can Reduce Risk
While frost quakes cannot be fully prevented, experts recommend several steps to reduce potential impacts near homes:
- Ensure proper drainage around foundations
- Redirect downspouts away from the house
- Fill low-lying areas where water pools near structures
- Seal small foundation cracks before extreme cold sets in
These measures help reduce the amount of water that can freeze rapidly in the soil surrounding a building.
What to Do If You Hear a Loud Boom
If you hear a sudden, thunder-like noise during an intensely cold night, experts advise staying calm. In most cases, it is simply the frozen ground reacting to extreme temperature changes. Unless visible damage is present, no emergency response is needed.
The Bottom Line
As Minnesota enters another stretch of deep winter cold, residents from Minneapolis to Duluth may hear unfamiliar sounds echoing through the night. While startling, frost quakes are a natural cold-weather phenomenon, not explosions or earthquakes.
If you’ve experienced frost quakes in your area or noticed ground changes during extreme cold, share your experiences in the comments below.
