Sinkholes can appear without warning. Depending on the sinkhole size, it can be a minor nuisance or danger to the traveling public.

Sinkholes are depressions in the ground surface.  They are caused when voids in the subsurface get large enough that the overlying material can no longer support its own weight and collapses into the void.  The void can be caused by groundwater dissolving and removing material, erosion around drainage features, and (most frequently in Colorado) mining operations.  The Geohazard Program performs emergency investigations when sinkholes begin to develop to determine the size and extent of the sinkhole.  

A drainage culvert under the highway collapsed causing water to erode out the soil around it.

Sinkhole caused by a collapsed culvert on I-70 near Vail.

An old, abondonded mine shaft that was unknown created a sinkhole.

Sinkhole caused by a mine shaft on I-70 in Idaho Springs.

This sinkhole developed when a 100 year old abandoned railroad tunnel collapsed.

Sinkhole on US-24 caused by a collapse of a 100 year old railroad tunnel under the highway.