A mile-long ice jam on the Delaware River is now causing flooding in some areas.
Large pieces of ice bunched up in the water around Trenton, N.J. as temperatures continued to bounce between the teens and single digits on Wednesday.
"It's not one solid sheet of ice across the top, you can see that it's many large chunks and it just goes...as far as the eye can see to the north," SkyForce10 photojournalist Jeremy Haas said.
The ice stretches for at least one mile and covers nearly every inch of the river from bank to bank -- which is an average distance of about 900 feet wide at that point.
In some areas, the ice pieces were pushing out of the river and onto the riverbank.
Free-flowing water was spotted in a few small sections of the river -- including an area around the iconic Lower Trenton Bridge.
Wednesday night, flooding from the backed up river pushed up the Route 29 exit ramp and froze in a matter of minutes.
Around 6 p.m., in Lower Makefield Township, an overflow of water rushed out onto Route 32 (River Road). The road is now closed between Black Rock Road and Trenton Avenue. Officials say the closure will be in effect until floodwaters from the Delaware River have receded from the highway.
River Road is currently being detoured over Black Rock Road, Pine Grove Road and Trenton Avenue.
The National Weather Service said several miles of the Delaware, to the north of the jam, is nearly at the top of its banks.
The conditions prompted the weather service to issue a Flash Flood Watch for towns downstream of the jam -- on both sides of the Delaware. They include Philadelphia and parts of lower Bucks County in Pennsylvania and Burlington and Mercer Counties in N.J.
"When this ice jam breaks, there may be enough water behind the jam to cause flash flooding downstream," the NWS alert read.
With temperatures remaining below freezing through Thursday morning, the NWS is warning that the jam may not break until then.
About 30 miles downstream in Philadelphia, the Delaware was still dotted with large sheets and chunks of ice. However, the ice was not packed together like in the Trenton area.
An ice jam was also reported along the Lehigh River just downstream from the Old Glendon Bridge in Easton, Pa. The jam caused water and ice to cover parts of Lehigh Drive. Officials say the jam should remain in place at least until Thursday morning. They warn all residents and businesses along the Lehigh River from the Old Glendon Bridge downstream to its confluence with the Delaware River to remain alert for "rapidly changing conditions" until the jam clears the area over the next few days.
The ice along the river is unstable and dangerous. Do not drive your vehicle into areas where the water covers the roadway. Also avoid touching, standing or going near the ice.
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Contact Vince Lattanzio at 610.668.5532, vince.lattanzio@nbcuni.com or follow @VinceLattanzio on Twitter.
Photo Credit: SkyForce10 - NBC10.com