WILMINGTON, Del. (CBS) — The Delaware Department of Transportation (DelDOT) announced an immediate closure of Bridge 1-813 over the Christina River on 1-495 that went into effect Monday evening.

DelDOT closed the bridge at 6 p.m. Monday because an inspection showed four of the 37 support columns are tilted as much as four percent out of vertical alignment. This is expected to cause a significant impact to commuters.

DelDOT says their bridge engineers and consultant are on the scene and are placing tilt sensors to monitor the bridge.

Bridge inspectors continued to assess support columns under the bridge Tuesday. They also plan to check a tilt meter installed Monday that will give them information on whether the bridge is moving.

“We’ve got our bridge engineers and bridge contractors who are examining the bridge. They’re putting a tilt meter on the bridge just to measure if the bridge is still moving,” Secretary of Transportation Shailen Bhatt said.

I-495 will be closed northbound at Terminal Avenue and message boards are in place on I-95 and SR 1 and Rt. 13. Local northbound traffic can stay on I-495 to Terminal Avenue. I-495 southbound will be closed at the Pennsylvania State Line. Southbound traffic will be directed to take I-95 southbound.

DelDOT says they received a report about an anomaly with a column late Friday. An inspection crew was sent out Monday morning. Additionally, DelDOT says a notification was received from a DelDOT Equipment Operator Monday morning who noticed a shifting of the concrete barrier on the road surface.

After reviewing the data and pictures, DelDOT’s bridge engineer recommended closure until further investigation can be done.

“I would not characterize it as ‘we were this close from disaster,’ it’s more of you know, we’ve got a situation that is abnormal and so we want to take the necessary steps to make sure that everything is safe,” Bhatt said.

The Wilmington Police Department advises motorists to seek alternate routes and exit I-495 prior to 12th Street if possible.

According to DelDOT, Bridge 1-813 over the Christina is a concrete deck on steel beams, built in 1974. DelDOT says it was last inspected in October 2012, and bridges of this type are inspected every two years. This section of I-495 carries about 90,000 vehicles daily.

Tuesday afternoon, DelDOT officials said a huge pile of soil on the north side of I-495 bridge in could also be to blame for column tilting. The owner was asked to move the dirt.

Officials say the bridge will remain closed indefinitely.