Ice-jam risks spur sandbagging call

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PHIL HOSSACK / WINNIPEG FREE PRESS U.S. National Guardsman strides out of Fargo�s Oak Grove Lutheran School. It flooded despite sandbags.

Provincial and civic officials cautioned Monday the break in flood-fighting efforts in the Red River Valley is just the calm before the storm.

Cold weather has slowed the spring melt, causing the Red River to rise not as quickly as first feared. But that could change as temperatures warm and thick ice on the rivers breaks up over the next week, triggering more massive ice jams and sudden flooding, as seen in the Lockport area last week.

Potential for ice jams -- flood fighters have never seen these conditions -- is high at each bend and bridge along the Red from Emerson to past Selkirk, including in Winnipeg.

"We have to remain at a high state of vigilance until the ice moves out," Manitoba's flood forecaster, Alf Warkentin, said at a flood briefing. "We almost have to expect another ice jam."

The threat of ice jams over the next 10 days prompted city officials to exhort residents living along low-lying areas of the Red River to get busy sandbagging, as many weren't taking the risk seriously enough.

On the weekend, city flood fighters asked 50 homes to hike their dikes by a foot and 30 more homes to start sandbagging because ice jams threaten to back water up over their properties. Crews visited each home and restaked dikes over the weekend, but not enough homeowners called to ask for another pile of bags.

"We're really encouraging people to do that," said Grant Mohr, the city's flood prevention engineer.

Mohr fears that homeowners see the Red River at levels that don't appear threatening and fail to grasp how likely and how fast an ice jam can develop, especially when the Red begins rising at a rate of about a half-foot a day later this week.

In Winnipeg, the Red River is solid ice from the Chief Peguis Bridge to St. John's-Ravenscourt School in Fort Garry. There are some open areas north of Bishop Grandin Boulevard, but other than that, the river is about as frozen as it was in February. Ice also covers it south of the city. Until that ice moves, the floodway gates can't rise to divert water into the floodway channel.

Kingston Row has plenty of freeboard on its new dikes, but residents south of the Perimeter Highway on Christie Road, Cloutier Drive and Turnbull Drive are at serious risk. Scotia Street, which is traditionally a flood hot spot, is well north of the target ice jam locations and is at lower risk.

Ice jams are most likely at the South Perimeter Bridge, along Kingston Row and at the Louise and Redwood bridges.

"We've got several weeks ahead of us yet," Emergency Measures Minister Steve Ashton said Monday. "We are not underestimating anything down the line."

The brief respite in sandbagging also prompted Manitoba Health to encourage people with health issues living in the flood zone to plan ahead: Buy extra medication, talk to their doctor, or temporarily relocate in case high water blocks roads.

Besides ice jams, another threat comes from overland flooding .

Ashton and other officials said many drainage ditches and culverts in southern Manitoba are still full of ice. Crews are busy working around the clock to thaw them so runoff from fields doesn't back up into peoples' homes. The threat of overland flooding is more worrisome because the ground is already saturated with water from fall rain and winter snow.

Along the Red River, flood fighters hope for a slow, gradual spring melt so runoff comes after the crest of flood water coming up the river from North Dakota.

Warkentin repeated that the province is still expecting a flood at a 1979 level and perhaps even less, which will mean some highway and road closures, including Hwy. 75 at Morris. It will also mean the full or partial closure of 18 communities. Already, Roseau River First Nation south of Winnipeg is now almost evacuated.

"The peak flow is going to be less," Warkentin said. "We're more prepared since 1979, but we're not taking anything for granted."

Provincial flood fighter Steve Topping said if ice jams develop anywhere along the Red, the province will deploy its two Amphibex ice-breaking machines, currently working north of Selkirk.

bruce.owen@freepress.mb.ca

maryagnes.welch@freepress. mb.ca

Republished from the Winnipeg Free Press print edition March 31, 2009 A5