The Grand River Conservation Authority is bracing for a spring flood season that could well be a little bit out of the ordinary.
It’s already been an unusual start to 2018 when it comes to flooding, with water from the Grand River twice forcing closures of Blair Road in Cambridge, which isn’t typically one of the first streets to be affected.
The issue, GRCA officials say, is the presence of ice jams in different parts of the river system.
“There’s a high potential for flooding from the ice jams that are currently frozen into the river system,” Stephanie Shifflett, a GRCA water resources engineer, said Wednesday.
Cambridge is considered the biggest concern. It’s the first time in decades the GRCA has seen a sizable ice jam in the city.
As Shifflett explains it, the issue is that ice moved downstream, then became trapped. When a flash freeze occurred, the ice was frozen in place – where it will remain until there’s a sustained spell of mild weather.
“There isn’t a whole lot to do to move the ice. Nature has to move the ice out,” she said.
When temperatures do get warm enough for long enough for ice to melt, the water can end up flowing in unexpected ways.
While the GRCA has a warning system in place, Shifflett says flooding can sometimes occur before a warning message can be sent out. As a result, she recommends that anyone living in a flood-prone area take precautions like moving out of basements and looking into flood insurance before the thaw.
The GRCA is also keeping an eye on the situation around Dunnville, where the Grand enters Lake Erie. A significant amount of ice has formed there.
“That ice will prevent any ice that’s coming from the river … from emptying into the lake,” Shifflett said. The result of that would be localized flooding.
Canadian Coast Guard icebreakers are occasionally to break up ice at the mouth of the river. It is possible that they will be called on again this year.
