The local conservation authority isn’t too worried about this week’s anticipated warm up in terms of potentially causing flooding along the Thames River.
Don Pearson, general manager at the Lower Thames Valley Conservation Authority, said staff were out last week measuring the snow load on the land that feeds runoff into the Thames River system. They also believe there’s about a foot of ice on parts of the river.
The potential is there for flooding, as there’s enough ice to cause a jam along the Thames, and more than enough snow to fuel rising water levels.
But Pearson just doesn’t see it happening this week.
“The ice level is close to the threshold that we track for potential issues. But the warm up will give us three or four days in a row above freezing, but the nights will go down to freezing or below,” he said. “I doubt that will be enough heat to create a rapid runoff.”
Pearson said the snow pack is also so fresh and that we haven’t had much in the way of warm weather that as it melts it will mostly condense for now. LTVCA officials call it “ripening” of the snow pack.
Pearson wants anything but that rapid runoff. A slow melt would help minimize the potential for flooding.
“It all depends on how quickly spring occurs,” he said. “With the amount of ice we have, if we had a rapid thaw and runoff, there would definitely be concerns.”
Most of the snow and rain we’ve had since Christmas is still on the ground, Pearson said, in the Thames River watershed. He’s heard the snow load in the London area is about 140% of normal, meaning there’s more snow than average on the ground there.
“That’s territory they’ve been in on other occasions. If we get a prolonged warm up with freezing temperatures at night, the snow and water can dissipate,” he said.
Pearson said the last thaw we had in January caused parts of the Thames to be free of ice, but left a build up of pack ice near Kent Bridge. It didn’t cause any ice jamming, however, as the water just flowed underneath it.
As with our cold weather and heavy snow this winter, we’re at the mercy of Mother Nature as spring approaches in terms of what will happen next.
“It’s just too early to tell, but we have the kinds of conditions that merit paying close attention to,” Pearson said.
He added he’s spoken with flood co-ordinators in Chatham-Kent and Lakeshore down river, and that stockpiles of sandbags are on hand in case they’re needed.