The subzero temperatures this week brought not only frostbitten fingers and high heating bills, but a major ice jam along the Allegheny River.
Now, another shift in weather is expected to send the blockage downstream.
The quarter mile long buildup is thought to be 5-to-6-feet high and is located just upriver from New Kensington’s Ninth Street Bridge.
The National Weather Service is predicting mild rainfall this weekend and temperatures are expected to exceed 50 degrees.
Werner Loehlein, water management chief for the U.S. Army Corps of Engineers, said the precipitation and warmer weather should loosen the ice before the temperatures drop below freezing once more.
“It will continue to deteriorate and the rain that’s coming on Saturday will pretty much flush it out and be clear,” he said. “And when we get the colder temperatures in the middle of next week again, that ice won’t be there to build on itself.”
Despite the mix of rain and melting ice, Loehlein said he’s not worried about any major flooding, but there are still concerns.
“We do have to be cautious that the warming temperatures will rot the ice and it could move at any time,” he said. “It’ll send these waves, sometimes several feet, down the river. Eventually, they’ll dissipate as they go down.”
Loehlein said if the ice breaks off, it could act like a small dam, causing choppy river conditions and raised water levels.
Pittsburgh’s towboats and barges have had the most trouble dealing with the ice, according to Loehlein. He said the blockage makes it impossible for the ships to move up and down the Allegheny.
“When the ice is relatively thin, you can sometimes just break through it,” Loehlein said. “It slows you down. But, if it jams up, then it pretty much acts as a roadblock and you can’t get through it. So, it basically halts navigation.”
Ice has also been noted on the Ohio and Monongahela Rivers, but no blockages have been reported.
Loehlien said the U.S. Army Corps of Engineers is also keeping its eye on a section of the Allegheny near Parker in Armstrong County, where the ice is starting to jam.