August 3, 2012

Column | Korky Koroluk

Extreme weather a wake-up call

Weird weather has been much in the news this summer.

Parts of North America have had it hot and dry; parts have been wet and cool. There’s nothing unusual in that.

What is unusual is the degree of heat, the extreme lack of rain in many areas, or the excessive rain in others.

There are already ramifications for all of us. As crops failed for want of rain in huge swaths of the central United States, food prices have begun to rise. Many livestock farmers have been forced to sell off parts of their herds because they have no fodder for them, and can’t buy it at any price.

There are ramifications for the construction industry as well.

As a result of extreme heat in the U.S., the drought in the southern plains states intensified. And as the clay-rich soils upon which many highways are built shrunk, extensive cracking showed up in the running surfaces.

As well, unusually high heat caused some sections of highways to expand beyond their design limits, resulting in slabs of pavement popping up to create a sort of speed-bump effect. Some of the bumps were so extreme that sections of some highways had to be closed.

Rail lines had to be closed because of “sun kinks,” a phenomenon that occurs when heat expands the steel rails to the point that they “kink”— bending sharply as a result of the stresses caused by expansion. There was even a case in one Atlantic coast city where a subway line kinked, derailing a train.

There was also an incident in which the wheels of a passenger aircraft awaiting its turn for takeoff, sank into the asphalt surface of a taxi path softened by heat exceeding 40 C. Unable to free itself, the aircraft had to be towed, and the undercarriage inspected before the plane could be allowed to fly again.

Where storms formed, they were big ones, knocking power out over wide areas. One rapidly moving system knocked out power for 4.3 million people in 10 states from the Midwest to the Atlantic coast.

The frequency of extreme weather has increased during the last few years, and the trend is likely to continue. Climate models tell us that infrastructure sensitive to weather will have to survive many more extreme episodes — as well as having to survive changing weather patterns involving more and higher maximum temperatures — as well as higher overnight minimum temperatures.

“We’ve got ‘the storm of the century’ every year now,” says one engineer ruefully.

In fact, one American utility company, in the space of just two-and-a-half years, has been hit with five storms that each had a recovery time of at least five days.

Things like that have utilities thinking of putting more of their lines underground. Often suggested in the past but discarded as too expensive, burying the wires, some think, would be cheaper than leaving them above-ground to be repaired again and again.

Tom Scullion, a senior highway research engineer at Texas A&M University, says highways are designed for the local climate, taking things like temperature and rainfall into account. But when you get extremes that fall far outside the norm, “then all bets are off.”

Shifting weather patterns, he said, mean “we could have some very dramatic failures of highway systems.”

So this summer of extreme weather should be considered a wake-up call for municipal and provincial governments, many of which have not yet given a lot of thought to our changing climate.

Some expensive work will be needed as we try to get our infrastructure ready for change.

The longer we put that work off, the more expensive it will all become.

Korky Koroluk is an Ottawa-based freelance writer. Send comments to editor@dailycommercialnews.com

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