NASHVILLE (The Tennessean) -- The arctic blast that gripped Middle Tennessee last week likely caused a giant boulder to fall onto Interstate 24 West Tuesday morning.
Engineers with the Tennessee Department of Transportation believe the boulder - about 6 feet tall and 12 feet wide - rolled off the top of the rock wall and fell into the eastbound lanes of the interstate between Old Hickory Boulevard and Briley Parkway just north of town.
Single-digit temperatures coupled with thawing ice caused the rocks to expand and shift, according to Tennessee Department of Transportation spokeswoman Deanna Lambert.
Rock slides are common in East Tennessee as ice freezes and then thaws. That's because rock cuts are generally steeper to the east, according to TDOT civil engineer Robert Jowers.
Slides are more unusual in the Nashville area.
It's even less common for rocks to make their way into roadways. Roads near rock walls are designed with especially wide shoulders and side ditches to keep debris from falling into lanes, Jowers said.
"It is not too often that we have debris of this size make it onto a major interstate in Middle Tennessee," she said. "TDOT is very thankful that no one was hurt."
On Tuesday, water was pouring down the rocks.
"It was like a waterfall on the side of the rock (wall) along I-24," Lambert said in an email.
Crews used a front loader to push the massive rock off the interstate. They will return in the near future to break the boulder into smaller pieces and move it.
Lambert said TDOT would provide more information if a temporary lane closure is necessary.
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