The rain that fell over many parts of our region earlier this week was very welcome. It’s been an unusually dry summer across a very large portion of Atlantic Canada; dry and hot!
On my drive into work Monday morning, while I was enjoying every drop of rain that hit the windshield, I was reminded of something that I don't often have to think about: slippery roads in the summer.
We know, from experience, that wet roads can be slippery. When it rains, the water on a road causes a loss of friction. As tires move over a wet road, the water fills in the tiny pits in the road surface, effectively smoothing it out. As a result, the normal heat and friction created between the surface of the road and the tire are decreased, leading to a surface that is more slippery than when dry.
If there's a lot of water on the road, including standing water in puddles, an even more severe loss of friction can occur. In these cases, a car's tires can completely lose contact with the road surface as they surf along on a thin layer of water. That terrible feeling is a result of hydroplaning and it’s very dangerous.
Did you know that roads are at their most slippery when wet weather comes after a long dry spell? This is because there are substances on roads that can lead to a loss of friction when water is added. For example, most dry roads contain a layer of tar, rubber, and oil. A prolonged spell of hot weather can cause these substances to build on the road’s surface. When it starts to rain, these can mix with the water, creating a greasy layer that can be very slippery.
My foot might have been a little heavy as the red light changed to green early Monday. A little spin of the tires quickly reminded me that wet roads require a gentler, more conservative approach behind the wheel.
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Cindy Day is the chief meteorologist for SaltWire Network