ALBANY - Engineers analyze mountains of data and consider the worst case to design roads and bridges that will withstand disasters like Wednesday's heavy flooding that tore a jagged gash across an upstate highway but it's a battle that nature still sometimes wins.

“There's always that dilemma when disasters occur, and people will ask you why you didn't design for it,” said Thomas O'Rourke, a professor of civil and environmental engineering at Cornell University. “Engineers do design bridges and roadways for a certain level of flooding, based on meteorological data, but sometimes damage is inevitable.”

O'Rourke, a former president of the Earthquake Engineering Research Institute, has provided assistance around the world on infrastructure design and disaster preparation.

He has studied how infrastructure fared during such disasters as the Sept. 11, 2001, terror attacks and earthquakes in California.

On Wednesday, flooding saturated much of upstate New York after record rainfall from the storm that had already battered the Mid-Atlantic, killing at least 10 people.

In the Binghamton area, 4.05 inches of rain fell in 24 hours. Just north of the city, a culvert failed beneath a section of Interstate 88, tearing a chasm between 15 and 60 feet wide in the highway. Two truck drivers died when their rigs crashed into the ditch.

Gauges on streams and rivers continually monitor the water flow, with some taking measurements for as long as 50 or 100 years to provide a statistical database about what drainage devices were used previously and the intensity of earlier floods, O'Rourke said.

Roads and bridges are then designed based on the data, preparing for the type of extreme flood that might only occur once in 100 years.

“Lots of things begin to happen during flooding that aren't in the picture under ordinary circumstances,” O'Rourke said.

Engineers also take into account scour, which happens when there's a lot of fast moving water that picks up more sediment than usual, basically excavating the terrain.

“In some rivers, under flood stages, erosion of the river bed occurs, sometimes down to about 50 feet below the water level,” said O'Rourke.

Engineers have to design for all of that, using hydrological benchmarks, but in situations like Wednesday's flooding, those design levels can be exceeded.

The scour may end up disabling bridges, or else heavy logs and trees can slam into bridge columns.

Under extreme flooding conditions, it's almost inevitable there will be some problems with destruction and damage to the best designed structures, O'Rourke said.

And weather will exploit any structural weakness it finds.

“It becomes extraordinarily expensive to plan for,” said O'Rourke. “The trick is to try to provide the most security without excessive expense.”