By Robin Culverwell

LOWER MAKEFIELD TOWNSHIP, Pa. (CBS) —   These cold temperatures have allowed ice to form all over the place,  including on the Delaware River.  Now there is a significant blockage of the river just south of the Route 1 bridge in Trenton.

And the National Weather Service has declared a flood warning for Bucks (Pa.) and Mercer (NJ) counties.

Officials say the river was 65-percent blocked by 1-2 foot chunks of ice this afternoon, leading to a seven-foot rise in the river level.

“It’s classified as a ‘serious restriction’ by the National Weather Service,” says Bucks County communications director Chris Edwards.    “Clearly all of our local emergency management professionals are monitoring the situation, particularly the municipalities in Bucks that are along the river.”

Edwards expect that nature will eventually take its course, clearing the blockage.  But in the meantime, flooding was occurring at Route 29 and Market Street in Trenton, and in the lower State House parking lot, adjacent to the river.

In Pennsylvania, River Road was closed between Black Road in Lower Makefield and Calhoun Street in Morrisville.

And because of the contour of the river, ice could jam up again closer to Philadelphia, creating further worries downstream.

Robin Culverwell