Thick icicles drooping down from the ceiling created a cool sight for motorists driving through the Hwy. 5 tunnel, which passes under Hwys. 55 and 62 near Fort Snelling and the Minneapolis-St. Paul International Airport.
Drive reader Willi described the spectacle as being about a yard long and a few feet wide. He saw icicles hanging primarily over the eastbound lanes as he drove west on Hwy. 5.
"It was like going through a cave with all the stalactites," he said.
Other motorists marveled at the frozen sight, too, but like Willi they were concerned that ice spikes could fall and damage vehicles passing below.
The icicles, which formed earlier this month with the arrival of the season's first cold snap, are long gone. MnDOT took them down.
"In order to protect the traveling public, when we become aware of an icicle situation, we remove them," said Duane Green Jr., MnDOT's maintenance operation engineer in charge of structures.
But that does not mean they won't be back. Green said icicles likely formed because the original and buried waterproofing system installed when the Fort Snelling Tunnel was built in 1961 failed due to its age and the constant freeze-thaw, expansion-contraction cycles. That allows water to seep through the overhead construction joint and form icicles similar to those that grow on edges of roofs during the winter, he said.
In extremely rare occasions, MnDOT will excavate and reseal a buried construction joint. In most cases, however, the agency will recaulk the exposed side of the joint.