Weather Explainers

Weather Words: Sinkhole

A sinkhole is a sudden collapse of the ground that happens when the rock or soil beneath the surface erodes away and can no longer support the weight above it.

I’m not sure about you, but anytime I see videos or images of a sinkhole swallowing entire homes or cars, it makes me feel very uneasy.

A sinkhole is a sudden, often dramatic collapse of the ground that happens when the layer of rock or soil beneath the surface can no longer support the weight above it. Most sinkholes form in areas with limestone or other easily dissolved rock, where naturally acidic rainwater slowly eats away at the underground layers.

Over years or sometimes centuries, hidden cavities are created. When the ceiling of one of those cavities becomes too weak, the surface layer drops, creating a hole that can be a few feet wide or large enough to swallow cars, homes or entire sections of a road.

More than 110 sinkholes formed in the Dover area of Florida during a freeze event in January 2010. Groundwater levels dropped to record lows as farmers pumped water to irrigate their plants for protection from the cold temperatures. The sinkholes destroyed homes, roads and sections of cultivated areas.
(USGS)

Some sinkholes develop gradually, causing subtle sagging or dips in the ground. But many form without warning, appearing as sudden, steep-walled holes. Heavy rainfall, flooding, construction, broken water mains and groundwater pumping can all accelerate the process by washing out the material supporting the surface.

In places like Florida, Kentucky and parts of Texas, sinkholes are especially common because the geology beneath the surface is naturally prone to dissolving.

While sinkholes can be dangerous and destructive, they’re also a natural part of the landscape in many regions. In fact, they help shape features like caves, springs and underground rivers. But when they open up in developed areas, they become a vivid reminder of how quickly the ground we rely on can change.

Jennifer Gray is a weather and climate writer for weather.com. She has been covering some of the world's biggest weather and climate stories for the last two decades.