Trenton's Emergency Management Team is preparing for the worst.
Already the ice dam has water backed up behind it forcing road closures on both sides of the river.
Route 29 in Trenton has been opened and closed several times as river levels fluctuate.
It opened again in time for Thursday evening's rush hour.
On the Pennsylvania side, they had to shut down Delaware Avenue near Morrisville as the ice overflowed the river banks.
Giant chunks of ice have been piling up for days against the Trenton Makes Bridge.
The fear now is that it may blow out suddenly as temperatures rise in the days ahead.
"If in fact the ice jam breaks then we'll have a rush of water which could cause flash flooding," Qareeb Bashir of Trenton Emergency Management said.
Emergency personnel are standing by ready to evacuate the low lying Island neighborhood of Trenton.
A small swift flowing channel through the ice shows how quickly the entire mess could speed downriver.
A Coast Guard cutter travelled up and down the river to break up the ice damn and keep the shipping lanes open. They got 2.5 miles south of the Route 1 Bridge before two feet of ice became too much to break.
For many, this is a spectacle they've never seen before.
They flocked to the river banks to take pictures of what some call a once in a lifetime event.
"Incredible. I came down here just to take pictures of this. My grandchildren would not believe this. This looks like something you'd find in Antarctica," Rick Wilson of Yardley, Pa. said.
Residents are now hoping that this ice dam doesn't make once in a lifetime history when it breaks up.