The closure started at 2:30 p.m and lasted about 10 minutes.
"They may look small in the picture, but some of these icicles weigh between 12 - 20 lbs," WSDOT officials said. "We wouldn't want to take the risk of it hitting a vehicle."
It's just one of a number of big icicles DOT crews have been dealing with around the Puget Sound area Thursday.
WSDOT tweeted other photos of large icicles hanging down under the Mount Baker tunnel and Mercer Island lid on I-90. (As to their yellow color, the DOT says it's from a combination of dirt and algae.)
And Seattle DOT crews said they were going to briefly close the Battery Street Tunnel along SR-99 for icicle removal there.
Temperatures in Seattle have been consistently below freezing since early Tuesday morning and were sitting in the upper 20s by early afternoon.