Water levels peaking but still normal
South Saskatchewan reaches flow of 700 m3/sec on Tuesday, not expected to threaten its banks even as rains continue
The South Saskatchewan River’s highest level so far this year was reached on Tuesday with about a week to go for the usual June peak.
“It’s been a wet spring, no question about it. For April, May and June, precipitation is about 30 per cent more than you normally would get and a lot more days with rain, too,” said David Phillips, senior climatologist with Environment Canada.
Rains Tuesday amounted to 18.2 millimetres measured at Medicine Hat Regional Airport. In some places it was as high as 30 mm, said Phillips. It’s the most the region has experienced on that particular day in 25 years.
Sitting at nearly 700 cubic metres per second, the South Saskatchewan River’s flow is still within normal bounds for this time of year — between about 200 and 900 cubic metres. This is when we typically see the highest normal flows in Medicine Hat, said Jason Penner spokesperson for Alberta Environment.
Rain Tuesday in Okotoks and southwest Alberta and the precipitation still expected — about 30 mm — is not expected to take the river beyond the normal range, said Penner.
Seven Persons creek in Medicine Hat is slightly higher than normal range for this time of year. Ross Creek has risen sharply recently but is also still within the normal range, according to Alberta Environment’s website.
Forty-four mm of rain amassed in the first 13 days of June, up sharply from the 28 mm norm. June typically sees about 65 mm for the entire month, said Phillips.
“June is your monsoon season. It is clearly by far the wettest month of the year, almost twice as much as July,” said Phillips.
This is triggered by the jet stream changing from a winter to a summer position and is moving across the province. Weather systems ride the jet stream and that often includes rain.
The July average is about 36 mm rain, roughly the same as the 37 mm in May 37, he said.
Environment Canada’s long range forecast indicates a break from rain for at least a week, said Phillips. Temperatures will be cooler than normal but it will give some time for water levels to settle down a bit.
We are edging closer to the historical dates of flooding in this region. The conditions that contributed to that flooding came both from local rainfall and snow melt in the mountains. Cooler temperatures help to ensure that snow does not melt too quickly, said Phillips.
Snow pillow data helps to determine how much snow melt to expect.
“The snow pillows are normal or at the bottom of their normal range, except Sunshine which is at the top of its normal range,” said Penner.