Officials in flood-ravaged Pennsylvania said the levees in Wilkes-Barre holding back the Susquehanna were under extreme stress, but they are hanging in there so far.

Jim Brozena, Luzerne County Flood Protection Authority executive director, told The Associated Press that the Susquehanna's level in Wilkes-Barre is the highest on record and well beyond the design for the levee system.

A broken flood gauge hampered officials' ability to measure the river's height. Officials raised the estimated water height by about 3 feet.

The U.S. Geological Survey on Friday estimated that the river had crested at 42.66 feet, which is way above earlier estimates necessitated by a broken flood gauge, and higher than the 1972 record of 40.9 feet.

Brozena said the river was dropping on Friday but the flood control system was at its extreme limits.

Authorities were forced to close countless roads in Pennsylvania and tens of thousands were order evacuated.

As much as 10 inches of rain has fallen in some places in the northeast of the U.S. this week. The flooding was fed by days of downpour from remnants of Tropical Storm Lee, just about a week after a dousing from Hurricane Irene.

More than 1,200 National Guardsmen have been deployed to Pennsylvania to help with recovery efforts, Gov. Tom Corbett said.

They have evacuated 60 people by ground and have rescued 76 people and six dogs by air, he added.

We face a public health emergency because sewage treatment plants are underwater and no longer working. Flood water is toxic and polluted. If you don't have to be in it, keep out, he warned residents.