Spring's Melting Temperatures Raise Ice Jam, Flooding Concerns
PITTSBURGH (KDKA) -- The source of our summer pleasure is stilled by winter's icy grip and quickly becoming a threat.
"We have several feet of ice around the Freeport area," says Joe Palko, the hydrologist at the Pittsburgh office of the National Weather Service, "and as you go north, it's upwards to six feet there."
With spring's warmer melting temperatures starting as soon as Sunday, Palko says that raises the concern "that the ice is going to have to move, and if we have rainfall, that could cause a problem with ice jams."
Ice jams form when large chunks of ice break loose and hit the riverbank or bridge piers, and sink to the bottom and pile up forming dams and creating flooding.
Add to the ice threat the blanket of snow lying frozen across the region just waiting for the sun's warming rays.
Werner Loehlein who directs water management for the U.S. Army Corps of Engineers says, "The upper Allegheny in particular has about 16 to 18 inches of snow on average above Franklin. That's a lot of snow. "
So on top of watching the ice and the snow, Palko says they also are keeping a wary eye on the forecast.
"Any rain coming in addition to the snow melt could further complicate the problems," Palko said.
Rain would speed up the snow melt and ice break up, and there's enough potential in both for flooding.
The Corps will be using all nine of its reservoirs to capture as much of the runoff as possible, but Loehlein points out, "The problem is we only control about a third of the runoff in the water shed. The other two thirds will melt and run off into the rivers.
Palko says Mother Nature is fully in charge and all they can hope for is the right thawing combination.
"Cool nights, warm days that would be ideal conditions to get rid of the ice," he said.
But it would get rid of the ice on all three of Pittsburgh's rivers and Loehlein says it would be better if the Mon melts first.
"We get our most significant rises when the Allegheny and Mon melt at the same time, and there's always that risk," he said.
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