Winnipeg Free Press - PRINT EDITION
Flood conditions similar to 2009
But won't be as bad as 2011, province says in new briefing
It's 2009 all over again.
A thick, heavy snowpack across much of the Prairies and a spring that gets later by the minute compelled the province on Tuesday to upgrade the flood threat to southern Manitoba from mild to a potentially major flood.
Simply, it won't be as bad as the flood of 2011 -- many flood victims are still living with that destruction -- but it could be as bad as 2009, depending on how the weather plays out over the next three weeks.
For those with short memories, the 2009 flood was pegged at that time as the second-worst flood to hit the province since the start of official records in 1912. That spring, just four years ago, severe ice jams north of Winnipeg on the Red River destroyed dozens of properties and 850 people were evacuated from their homes at Peguis First Nation when the Fisher River burst its banks.
Officials said at the province's second flood briefing of the spring those same weather and water conditions experienced in 2009 are repeating themselves this year.
"It's clear we're going to be into flooding this spring and we are working around the clock to be prepared for it," Infrastructure and Highways Ministers Steve Ashton said.
Officials also said the colder-than-normal temperatures will cause a later spring thaw, which in turn increases the likelihood of a rapid snowmelt, threat of river ice jams and overland flooding. All that runoff hits a wall when it meets river ice that is still breaking up.
"Because of the delayed melt that we have we could be into a very rapid melt in which that American water and water in our tributaries could meet up against solid ice, so the ice-jam potential in Manitoba is very high," said Steve Topping, executive director of hydrologic forecasting and water management.
Persistently cooler temperatures late into the spring also increase the likelihood the melting snowpack and normal spring rains will happen at the same time, increasing runoff.
That runoff flows more quickly because it can't be absorbed into the ground, which is frozen up to 100 centimetres in depth in some places due to our cold winter.
So, with that, here's what the province expects to see in Manitoba's flood zone over the next few weeks:
Red River Valley
Highway 75 at Morris will most likely be shut again due to flooding along the Red and Morris rivers. In 2009, the main route between Winnipeg and the United States was closed for 36 days.
Ring-diked communities and individual properties will also likely be surrounded by water as the Red Sea forms yet again south of Winnipeg. All homes south of the city were elevated or built to be protected from major flooding after the 1997 Flood of the Century.
The province says minor to major flooding is now anticipated along the Red, fed by the melting thick snowpack that covers much of the basin.
Again, depending of the weather, levels along the Red River will be higher than in 2011 but slightly less or the same as in 2009 from Emerson to Winnipeg. The Red River Floodway around Winnipeg will also be called into operation to keep the city dry.
In Winnipeg, forecasters believe the Red River will hit 17.7 feet above sea level at James Avenue (the city's main measuring stick for the Red) with good weather, 18.8 feet for normal weather and 20.5 feet if weather conditions turn ugly. The 2009 flood peak at James Avenue was 22.6 feet.
There is a risk of moderate to major flooding on the Assiniboine River due to normal to above-normal average soil moisture in the upper portions of the watershed and the above-normal snowpack in Saskatchewan and parts of Alberta.
That means the Shellmouth Reservoir will control much of that flow, but just barely.
"There's so much snow in Saskatchewan that we think under all three weather scenarios, the Shellmouth will completely fill and will experience spillway flows," Topping said. "There's that much water stored in the snowpack upstream."
A bad-weather scenario would result in major flooding of the Assiniboine Valley from Shellmouth to Brandon similar to the levels of 1974, but lower than those of major floods in 2011, 1995 and 1976. Brandon flood-protection works are currently higher than the predicted flows.
The Portage Diversion will also be called into service to divert water from the Assiniboine into Lake Manitoba to prevent ice jams on the Assiniboine. Lake Manitoba is forecast to be at the top of its operating range of 812.5 feet above sea level this spring, but four feet below what was experienced in 2011 when severe flooding destroyed hundreds of cottages, homes and farm properties.
High on the flood-watch list is Peguis First Nation, about 145 kilometres north of Winnipeg. With poorer weather, the Fisher River could experience major flooding, with levels slightly higher than in 2009.
Ashton said he's already spoken to Peguis Chief Glenn Hudson and Assembly of Manitoba Chiefs Grand Chief Derek Nepinak on the threat. The province is ready to sandbag at-risk homes and will have heavy equipment in position to unclog ice jams at the community's bridges to reduce flooding caused by ice.
In 2009, a state of emergency was declared in Peguis, with 850 people evacuated. At the peak of the flood, 296 homes were affected, 169 of them seriously damaged.
It's been estimated 480 or more homes on the reserve need to be flood-proofed or relocated.
So far, so good.
"In general terms, the Souris River is about half of what it was for flood potential in 2011," Topping said.
It means, at this stage anyway, we won't see a flurry of dike-building and sandbagging in places such as Wawanesa or Souris. To the south, Melita has a ring dike.
Red Deer Lake
This is the hot spot for major flooding and potential evacuations this spring. Melting snow in Saskatchewan is forecast to flood the lake north of Swan River this spring.
Republished from the Winnipeg Free Press print edition March 27, 2013 A3
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