DULUTH -- Duluth's Aerial Lift Bridge has not been operating since Monday morning, a city official confirmed. Vessels traversing in and out of the Duluth port will temporarily use the Superior, Wis., entry.

“A team is down there doing analysis,” Duluth city spokesperson Kate Van Daele said. "They haven't found anything yet, but it can't go up."

There is no timetable for if or when the bridge will be back in operation.

According to the city of Duluth and the National Weather Service, Duluth officially received 21.7 inches of snow as of noon Sunday, which ranks as the ninth-highest two-day storm total in Duluth history. Given the number of post-blizzard issues associated with digging out the city, Van Daele was not hopeful the city would know more about the bridge issue Monday. She said the city would communicate results once it knows more.

Using the Superior entry will require vessel captains to be extra cautious, the Duluth Seaway Port Authority said.

"The Superior front channel is slightly shallower than the Duluth ship canal and Duluth harbor basin, so captains must navigate with extra caution, particularly near some of the shoal areas," Port Authority spokesperson Jayson Hron said. "Additionally, the Superior front channel is longer than the Duluth entry, so rerouting to the Superior entry can equate to higher costs due to the additional time required to bring the ship through the Superior front channel to its Duluth destination."

Since its modification in 1929 to include the raising and lowering bridge deck, the Aerial Lift Bridge has been rehabilitated four times, 1986, 1999, 2007 and 2009, with each project addressing different needs, the Minnesota Department of Transportation website said.

MnDOT said past rehabilitation efforts generally included replacement of the operator’s house, select structural steel elements, the bridge sidewalk and retaining walls; repairs to the abutments, deck grating, machinery, superstructure and lighting system; bridge cleaning and painting; and guardrail.

The iconic bridge raises and lowers thousands of times a year to allow for ore boats, foreign ships, U.S. Coast Guard vessels and recreational vessel traffic to travel through the Duluth ship canal.