July 20th, 2018

Hat still safe from flooding, for now

By Gillian Slade on April 17, 2018.

Chunks of ice piling up on the South Saskatchewan River near the Trans-Canada Highway on Monday morning after a sharp increase in river flow over the weekend.--NEWS PHOTO GILLIAN SLADE


Water levels in the South Saskatchewan River rose sharply Sunday, depositing on the edges large chunks of ice that were still clearly visible Monday.

The river level in Medicine Hat was at 3 metres until the early hours of Sunday when it increased to 4.50m before falling back to 3.25m on Monday, according to Alberta Environment.

“I was watching the river yesterday, it was quite impressive with the ice floes,” Mayor Ted Clugston said Monday.

While several areas of southern Alberta are experiencing flooding, there has been no warning or advisory for Medicine Hat as of yet.

Medicine Hat is perhaps as prepared as ever for potential high water in the coming weeks, thanks to numerous mitigation measures added since the disastrous flood of 2013.

“I think it would be interesting for the community to see the water come up and be held back, not all the way to the top of the berms but a third of the way up or something like that to see that they worked,” said Clugston.

There would be benefits to that: A whole new comfort level, and even a potential financial gain, he says.

“Insurance companies have still been somewhat reluctant to lower some of the rates down in the low lying areas, and I think if they see that the berms actually do work that might be a benefit for homeowners …,” said Clugston.

The flow in the South Saskatchewan River, measured in cubic metres per second, is an indication of the possibility of flooding. On Sunday in Medicine Hat it was about 76 m3/s. In comparison on June 22, 2013 the peak flow of the South Saskatchewan River reached 5,040 m3/s locally. The peak during the 1995 flood was 5,110 m3/s.

The snowpack in the mountains is almost 50 per cent more than usual this year, prompting Alberta Environment last week to issue a “spring runoff advisory” about the possibility of overland flooding.

It is also likely another six weeks of snow accumulation could occur before spring weather fully arrives, said David Watson, river forecast engineer for Alberta Environment.

The mountain snowpack is not the biggest threat to flooding though, providing the melting takes place slowly.

“What will drive flooding coming out of the mountain water courses would be a large and sustained rainfall, with or without a snowpack,” said Watson.

Of concern is the possibility of ice chunks breaking away from the snowpack and causing blockages in streams and rivers, said Watson. Rapid water level fluctuations can occur without warning where ice jams are an issue.

Clugston says he watches the river every day from his office at city hall, and frequently walks on trails along the river in the mornings. He has his own markers on the landscape to give him an indication of the river level. Although the level is up, he says, it is nowhere near any need for concern at this stage.

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