Jan. 18–Emergency officials are closely monitoring a monster ice jam measuring 2.5 miles long on the Allegheny River between the Tarentum and New Kensington bridges.
Although the movement of the colossal ice mass is unpredictable, it could cause localized flooding and property damage later this weekend when warmer weather arrives, according to the U.S. Army Corps of Engineers, which operate the locks and dams on area rivers.
Emergency officials have been watching the ice pile up since Saturday, following two weeks of freaky weather that ranged from subzero temperatures to the mid-60s along with snowstorms and appreciable amounts of rain.
The U.S. Coast Guard, the Corps, county emergency officials and swift water rescue teams are prepping for potential flooding, property damage — and rescues.
“We have the potential for a great deal of ice coming down the river,” said Ian McKelvey, Corps supervisor of operations for the Allegheny River.
At risk is localized flooding and damage to anything along the river’s edge in up to 15 communities from the Tarentum-New Kensington ice jam to Pittsburgh, as well as a slate of business and utilities — including two power plants in Springdale, according to Matt Brown, chief of Allegheny County’s Department of Emergency Services.
Brown could not remember in recent times the formation of such a large ice jam so close to Pittsburgh.
“Historically, those kinds of jams happen much farther up the river,” he said.
Officer Travis Magee with the Coast Guard warned: “We just want to stress that mariners be cautious of chunks of ice flowing down the river.”
If large chunks of the ice jam move farther into the more populated areas of Allegheny County, there are concerns for boat owners who still live in their houseboats docked at some marinas. Those mariners in the path of the ice flow were warned of the dangers earlier this week, according to Brown.
“The potential impact of the ice is unknown,” he said.
Allegheny County is prepared to activate its emergency operations like it did last weekend when ice jams caused localized flooding in a number of communities along local waterways.
George McBriar, chief of Blawnox’s volunteer fire company and chief of Allegheny County’s swift water rescue team, said they have alerted other water rescue teams in neighboring counties to be on standby for potential flooding issues in the region.
McKelvey and others best hope is for the ice jam to break up slowly then continue down river, ultimately making its way to the Ohio River.
Second ice jam
They have also been watching a second ice jam, its size undetermined, farther north on the Allegheny in Armstrong County between Lock and Dam 5 in the Schenley section of Gilpin and Lock and Dam 6 in South Buffalo — where the dam is no longer visible because it is completely iced over.
The Allegheny at that ice jam is about 10 to 12 feet higher than normal, according to McKelvey.
Additionally, ice has been flowing from the Kiski River to the Allegheny River, suggesting there was an ice jam on the Kiski that broke free.
“There a potential for flooding on the Kiski at any time,” said McKelvey. “There’s a potential for flooding everywhere near the rivers.”
The loose ice can get hung up on riverbanks and at the confluence of tributaries, causing mini-ice jams that back up the tributaries.
That’s what happened last weekend when flooding hit small sections of a number of communities including East Deer, Tarentum, the Natrona section of Harrison, Harmar and others.
Bull Creek in Tarentum jumped its banks a second time in five days on Tuesday night but receded early Wednesday, according to McKelvey.
Mary Ann Thomas is a Tribune-Review staff writer. Reach her at 724-226-4691, firstname.lastname@example.org or via Twitter @MaThomas_Trib.