An ice jam in the Delaware River is forcing water on to area roadways in an unusual winter overflow reminiscent of the January 1996 flood that led tens of thousands to evacuate throughout the mid-Atlantic region and damaged the State House Annex in Trenton.
"The ice jam and flooding is a big question mark," said NBC10 First Alert Meterologist Bill Henley.
For now, the Delaware Valley can enjoy a slight warm up from the record-breaking cold temperatures that hit the region earlier in the week.
Temperatures passed the freezing mark Thursday and will rise to a high of 44 degrees Friday with a chance of rain showers.
The mercury will soar Saturday, hitting highs in the low 60s with a high likelihood of precipitation.
And if the rains are heavy, it could cause even more problems in flood-prone areas.
"If the ice jam is still in place on Saturday night and we get heavy rain, it is impossible to predict how bad the flooding is going to be," said Ray Kruzdlo, a senior service hydrologist with the National Weather Service.
Water levels are already falling upstream and they are expected to drop in Trenton soon, Kruzdlo said. Normally that would be a good sign, but the ice jam complicates matters.
Water has been flowing downstream so far despite the blockage the ice creates, Kruzdlo said.
But we don't know what restrictions the ice jam will cause when the storm passes through this weekend, he said.
"It is a wait-and-see game with these things," he said. "Jams are very erratic."
Regardless of the inches that fall, officials doubt flooding will be as severe as the area experienced in January 1996.
"In 1996 we had a different set of circumstances," said Clarke Rupert, spokesman for the Delaware River Basin Commission. "There was a combination of a lot of snow on the ground, heavy rains and really warm temperatures."
"Back in the 1996 flood, there were much larger ice jam issues up and down the Delaware River," he said.
This time around the mile-long ice jam stretches from the area about a half-mile south of the Route 1 bridge to just past the Calhoun Street bridge, Kruzdlo said.
It stretches 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.
"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," said SkyForce10 photojournalist Jeremy Haas while looking at the jam from the air.
The Coast Guard sent boats upstream Thursday to break up the ice jam and help loosen any restrictions preventing water from flowing downstream.
The 65-feet-long tugs encountered ice up to five-feet thick on the river about three miles south of Trenton, according to officials.
Large pieces of ice first bunched together in the water around Trenton, N.J. and Bucks County, Pa. on Wednesday as temperatures in the teens continued to make conditions ripe for freezing.
Water, displaced by the ice, spilled out of the Delaware and began to creep onto roadways and into structures.
The New Jersey Statehouse garage, some southbound lanes on Route 29 in Trenton, N.J. and Route 32 north in Yardley, Pa., closed Wednesday because of flooding and remain closed Thursday afternoon.
A overflow of water also rushed out onto Route 32 (River Road), in Lower Makefield Township, Pa. on Wednesday evening. The road is now closed between Black Rock Road and Trenton Avenue. Officials say the closure will be in effect until flood waters from the Delaware River have receded from the highway.
Worried that the flooding will get worse as the ice begins to melt with temperatures rising on Thursday, forecasters with the National Weather Service issued a Flood Warning for parts of Mercer County in N.J. and Bucks County in Pa. until 8 p.m. Friday
The NWS also extended a Flash Flood Watch for areas downstream from the ice jam -- including Philadelphia, Trenton, Moorestown, Mount Holly, Morrisville and Doylestown -- until Friday morning.
"When this ice jam breaks, there may be enough water behind the jam to cause flash flooding downstream," the NWS alert read.
Forecasters say the river is at 19.3 feet and fluctuating below the flood stage of 20 feet. The river is expected to fluctuate throughout the day.
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. The jam, which was still in place late Thursday morning, led officials to exten its flood warning for southcentral Northampton County. 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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Photo Credit: SkyForce10 - NBC10.com