logo
Sinkholes; A Whole Lot of Danger
news image
Special Stories
26 Feb 2018 7:54 PM
With the ongoing flooding occurring from the Great Lakes to the Gulf Coast and more to come, it’s a good time to review why not to drive through flooded areas.  You see there is an underlying danger in parts of the country that is often lurking just below flood water that can swallow a car whole.  Sinkholes are that hidden danger and can often form under pavement or concealed by water. Sinkholes are most common in what is called “karst terrain.”  These are locations where rock below the surface can be dissolved by groundwater.  These soluble rocks can include salt beds, limestone, gypsum and other forms of carbonate rock. Take for instance areas that are underlain by limestone, a type of rock that is slowly dissolved by weak natural acids found in rain and in the pore spaces in soil. Dissolving the limestone creates underground caverns below the surface of the earth.   Over the limestone many times we find a fairly thick layer of clay mixed with sand which can remain intact and suspended above the void caused by the erosion.  One type of sinkhole that can occur is called a cover collapse sinkhole.  Basically the material above the eroding limestone has enough cohesion to hold its shape for a while, but the problem comes when this material loses that cohesion and collapses. Sinkholes can form because of extreme rainfall and because of prolonged drought.  Our recent heavy rain added a large amount of rain and weight to the surface material and from that we can see sinkholes.  In many cases the underground caverns have a thin ceiling but when the weight gets to be too much that ceiling ceiling can fail and the cavern fills in from material above. Sinkholes can also form during and after times of drought.  During droughts underground caverns that might normally be filled with water may be only partially filled. These cavities are less likely to bear the weight of the material above especially when weighted with flood waters or vehicles without collapsing. When flood water covers the road, a sinkhole or the start of one, may not be visible and bad things can happen to drivers who don’t heed the warning Turn Around, Don’t Drown. If you live in an area prone to sinkholes and water covers a section of road in your path it may be best to find another route. Meteorologist Mike Morrison
All Weather News
Snow Returns to the Rockies and Cascades
Snow Returns to the Rockies and Cascades
Snow is in store for the northwestern U.S. mo
22 Mar 2023 10:35 PM
Heavy Rain & Flood Threat for the Ohio Valley Late Week
Heavy Rain & Flood Threat for the Ohio Valley Late Week
In addition to severe storms, heavy rain is e
22 Mar 2023 10:20 PM
Tornado Touches Down in Los Angeles area Wednesday Afternoon
Tornado Touches Down in Los Angeles area Wednesday Afternoon
CALIFORNIA - An apparent tornado touched down
22 Mar 2023 7:55 PM
Severe Storm Chances Return to the Plains & South Late Week
Severe Storm Chances Return to the Plains & South Late Week
A strong upper-level low-pressure system movi
22 Mar 2023 7:50 PM
Avalanches in Colorado Claim the Lives of Two - Avalanche Alerts Continue this Week
Avalanches in Colorado Claim the Lives of Two - Avalanche Alerts Continue this Week
FOUR CORNERS - Fresh snow is leading to unsta
22 Mar 2023 7:45 PM
Strong Storms & Flooding Target the Midwest Today through Friday
Strong Storms & Flooding Target the Midwest Today through Friday
With the jet stream focused over the Midwest,
22 Mar 2023 7:40 PM
Record Heat to Finish Out the Week in the Southeast
Record Heat to Finish Out the Week in the Southeast
Relief from the cold is back in-sight, just i
22 Mar 2023 7:35 PM