By Graeme McNaughton/The Oshawa Express
Residents in the city’s downtown on Friday night may have gotten a little bit wet.
Between 10 p.m. and 10:30 p.m., the city was hit with heavy rains, leading to flash floods downtown after the city’s storm drains could not handle the heavy load.
According to Geoff Coulson, a warning preparedness meteorologist with Environment and Climate Change Canada, Oshawa was hit with approximately 31 millimetres of rain in that half-hour span.
“In this particular case, it’s a combination of the time involved, as well as the amount. A 30-millimetre rainfall over the course of 12, 18 hours would be a good soaking,” Coulson tells The Oshawa Express.
“This rain was very intense. That rain falling, instead of being spread out over a whole day, fell in about 30 minutes.”
According to statistics from Environment and Climate Change Canada, Oshawa received 32.6 millimetres of precipitation in the entire month of June, and 23.9 the month before.
According to Derrick Clark, Oshawa’s deputy fire chief, the city’s fire department received approximately 70 calls in Oshawa, Whitby and Clarington for assistance for matters ranging from cars being stranded in high waters, flooding, lightning strikes and hydro wires being knocked down.
“It just seems that the thunderstorms are getting more severe in nature. They come in so quick, and they’re very forceful,” Clark says.
“I think the problem with this one was, I believe, is that the ground is so hard because of the drought conditions we’ve been having, so the water wasn’t getting saturated into the ground and was just running right off. That’s why it overwhelmed the storm system.”
In the event such a flood happens again, Clark advises motorists to stay off the road if they can avoid it.
“In those conditions, people should just avoid driving and keep where they are, or even pull over at a safe place and just wait it out,” he says.
Coulson adds that those planning any activities outdoors should keep an eye on weather reports to ensure they do not get stuck in heavy rains such as these.
“We had a watch out for the area at around eight o’clock on Friday evening and it was upgraded to a warning at about 9:20 p.m. So, there was a lead time of about 40 minutes before the heavy rain really started. That’s fairly typical for these types of storms,” he says.
“Usually the watches will give a few hours advanced notice for the potential for these types of strong storms, and the warnings will give anywhere from half an hour to an hour’s notice that these storms are likely to occur.”