When her children were small, Mary Campbell took them hunting for frogs in what is now a residential neighbourhood in High River known as Hampton Hills. “It was a swamp,” she recalls from her farm home, overlooking a sprawl of new suburb. So she wasn’t surprised when the flood that swept through the town last summer hit the upscale new housing development particularly hard. “The town should never have allowed houses to be built there,” she says.

Like everyone else in High River, the energetic 80-year-old was ordered to flee the rising waters last June 20th. “That was the worst flood I had ever seen in my 55 years in High River,” she says, describing the water rushing over the banks of the Little Bow Canal just below her homestead, uprooting trees and carrying away vehicles and livestock. “It was a tsunami.”

This wasn’t the first time the town, about a half-hour south of Calgary, lived up to its name. But for a community that measures time according to natural disasters, the flood of 2013 topped all others. The torrential rush of water from the Rocky Mountain foothills forced the evacuation of all 13,000 High River residents, including some 150 rescued from their rooftops. About 1,000 lived much of this past winter in a camp of trailers just north of town, waiting for their homes to be repaired or rebuilt.

The flood killed five Albertans, three of them in High River. Damage across the province was extensive, from Canmore to the Siksika reserve to as far downstream as Medicine Hat. The rising Bow and Elbow rivers put Calgary’s downtown under water for the first time in a century and destroyed some of the priciest real estate in the country. More than 100,000 people province-wide were evacuated from their homes at least temporarily.

The repair bill is expected to reach $6-billion, of which Alberta taxpayers are on the hook for at least $1.7-billion—a dear sum, particularly when the provincial government is already pleading poverty as justification for cutting education and healthcare spending. The rest of the cost will be paid out of federal government coffers, also billed to taxpayers, and from homeowners across the province through uninsured damage and higher insurance premiums.

The 2013 flood was the costliest weather disaster in Canadian history, and High River is considered “ground zero.” But had the Conservative government learned from the province’s three most recent floods, in 1995, 1997 and 2005, billions of dollars worth of property loss may have been spared all across southern Alberta—including the area where Mary Campbell and her children used to catch frogs.

“We had no indication it would flood. None of the province’s information suggested the area was prone to flooding.” —Developer Don Sandford

Officially speaking, Hampton Hills wasn’t supposed to flood. The neighbourhood is built not exactly on hills but on a ridge that appears to be a safe distance from the Highwood River. Although its bowl-shaped composition of fine clay left it marshy in rainy years, the neighbourhood wasn’t flagged in Alberta Environment’s maps as a flood risk, so town council approved it for development in 2005. The typical suburban lots for two-storey homes were snapped up quickly.

A computer-generated simulation on the town’s website shows best how the area flooded. The virtual Highwood River initially resembles a thin yellow trickle bisecting the map. The line widens and spreads with the contours of land, forming big yellow blotches. About 24 sped-up hours after the water starts rising, the river rushes back across Highway 498 north of town into Hampton Hills. By hour 36, almost all of High River is covered.

“There was just that much water and it found a depression and stayed there,” explains mayor Craig Snodgrass, elected last fall to his first term. “In the rest of the town, the water was gone in a day or two, but The Hamptons was under water for a long time.” It took 25 days to pump out the area and allow residents back. “All the emergency measures we had in place were overwhelmed,” Snodgrass said. “No one predicted anything that would be three or four times what we’re used to.”

Maybe somebody should have. Changing weather patterns and the increasing damage they cause have been well documented over the past half-century. Still, many of Alberta Environment’s flood-risk maps were badly out of date and based on invalid assumptions of so-called 100-year floods. Unlike the US, Canada no longer has a national system of flood mapping; the federal government cut funding to it in 1992. The Alberta–Canada Flood Hazard Identification Program began in 1989 in response to extensive flood damage in the early 1970s. The program was ended 10 years later—a responsibility, critics say, the provincial government let lapse. The province admits “the program expired… before flood hazard studies and mapping were completed for all of the original candidate communities.”

Despite the provincial program’s cancellation, Alberta flood maps were still supposed to be updated if there was a change in the local hydrology. High River’s map was not updated following the 1995, 1997 or 2005 floods. When the big one hit last year, the town was still working with data that hadn’t been substantially revised or updated in 30 years.

The flooding in Hampton Hills could offer a grim foretaste of things to come for Alberta and the rest of Western Canada. Referred to by some as the province’s Hurricane Sandy, the flood of 2013 may mark the moment when Albertans finally acknowledged climate change and its widespread consequences. Andre Corbould, the former brigadier general who chairs the government’s flood-recovery task force, says Alberta needs a new way of looking at how we live with nature.

“Climate variability is a key issue,” Corbould says. “We know there will be more floods. We need to take an overall watershed approach. That means dealing with floods in the wet years and drought in the dry years.”

Areas in the province threatened by floods could increase by as much as half in less than 40 years, a government-sponsored symposium on flood mitigation was told last October. “Why are we getting floods impacting every corner of the world?” asked Scott Edelman, with the international engineering firm AECOM, which specializes in remediation of natural disasters such as hurricanes Katrina and Sandy. “It’s for two main reasons—population growth and climate change.”

Alberta, currently with about four million people, will likely have a population of six million by 2041, he says. Based on results from his firm’s study on the impact of climate change on US waterways, Edelman predicts flood plains in this province will increase by 30 to 50 per cent by 2050. “You have all this new population growth, which is impacting where people live, adding to more flooding,” he said. A growing population, in other words, translates into more people and more property in harm’s way.

“Essentially, we do not want a bunch of properties in the middle of a floodway,” says Corbould. “We want to protect the integrity of the floodway so it can do what it is meant to do, which is to allow the flood waters to go through and not hurt people or the economy.”

Alberta Environment and Sustainable Resource Development’s flood maps don’t do enough to reflect climate change. The ministry is redrawing them, expanding the areas considered prone to flooding. The new maps, which will tell municipalities where they can and cannot approve development, will assess risk based on a 100-year flood policy and identify areas that have at least a one-in-100 chance of flooding in any given year. But the recent cluster of floods exceeding predictions suggests the probabilities have changed.

“What we saw in the flood of 2013 was more than a 1 per cent chance,” Corbould says. “We will review the recent cycle of floods and come up with better information for avoiding floods.”

The public has heard much of this before, however. After the High River flood of 2005, Conservative MLA George Groeneveld was appointed to head an inquiry to look at ways to lessen the impact of future disasters. He submitted a report in 2006 calling for updated flood maps and new restrictions on development in flood-prone areas, including a ban on the sale of flood-plain land for development and a system of notification and disclosure for sellers and buyers of property on flood plains.

The report was shelved for six years and only released a year before the 2013 flood, its key recommendations having been ignored. They are now part of the government’s Flood Recovery and Reconstruction Act, passed by the legislature over the winter. Groeneveld believes the suggestions would have made a difference had they been adopted sooner. “The most important recommendation was not to build on a flood plain,” he says. “If that had happened, that would have cut down some of the damage, because I’m sure there has been some building on flood plains in the 60 communities the report covered.”

“What scares me is that once we get further away from the flood of 2013, we’ll lose that sense of urgency.” —George Groeneveld, former MLA and author of an ignored 2006 flood mitigation report

Without question, the flood of 2013 followed an unusual nature event. By some estimates, 220 mm of rain—half the total expected precipitation for the year—fell in the High River area in less than 48 hours. The Highwood River, which has a normal June flow of 30–70 m3 per second, rushed at 50 times that amount on June 20th—about 1,800 m3 per second. During past floods, the Highwood’s flow was 671–803 m3 per second.

Higher up in the foothills, 350 mm of rain fell over a three-day period. “Whenever you have more than 150 mm of rainfall in that short a period, you’re at great risk of flooding,” says John Pomeroy, who holds the Canada Research Chair in Water Resources and Climate Change at the University of Saskatchewan and does much of his research in the Alberta Rockies. He says rain on snow added to greater than normal snowmelt flows, while still-frozen soils 50 cm underground kept the precipitation from soaking into the forest floor and meadows, filling up streams that much faster.

The excessive rainfall was attributed to low-pressure systems over the Rockies trapped by high-pressure systems bringing record high temperatures to Yukon and Alaska, and to a high-pressure system responsible for a record number of forest fires in Colorado. “This wet weather system had nowhere to go, so it just stayed and dropped a lot of moisture on a relatively small area,” Pomeroy says. “When you start to have weather events like this that are really very different from any we have seen before, you have to ask yourself: Was it due to climate change?”

As bad as it was, though, he says 2013’s wasn’t the flood of the century. Pomeroy’s statistical review found that it amounted to only a once-in-32-year flood for the Banff area and once-in-45-years at Calgary, giving weight to the argument that the province should have anticipated the event and been much better prepared.

Indeed, the province has a habit of not learning from the past. The studies that informed Calgary’s old flood maps showed flooding in 1879 and 1897 with estimated peak flows 20 per cent higher than what was experienced in 2013. Despite a flood in 1915 that washed out Calgary’s Centre Street Bridge, much of the city’s downtown—including the newly developed East Village—remains on a flood zone today. And although 2013’s Flood Recovery and Reconstruction Act prohibits new development on flood plains, it exempts Fort McMurray and Drumheller, instead putting its faith in flood-mitigation plans.

Despite their skepticism in the past, the provincial Conservatives appear to accept anthropogenic climate change as the likely cause of unusually destructive weather. As a result, the province has undertaken a number of measures to be ready when future storms hit and to mitigate their impact when they do. The package includes immediate fixes such as higher dikes and waterproofing measures for homeowners who choose to remain on flood plains. It also includes a number of costly diversion projects modelled roughly after the 50-year-old spillway channels that divert excess water from the Red and Assiniboine rivers around Winnipeg.

The province plans to construct four headwater berms with dry ponds in the foothills—two on the Elbow River, two on the Highwood—and a foothills dam and pond on the Sheep River. These would dam up their rivers during times of heavy rainfall or spring runoff and store the water in a reservoir, to be released gradually. Instead of seeing a fury of water rushing through the river system over 24 to 48 hours, as happened on June 20, the flow would be spread out over 10 to 14 days, avoiding most of the damage.

The plan also includes water bypass systems around High River and much of Calgary. The latter would allow managers to divert floodwater from the Elbow River through an underground passageway along 58th Avenue and deliver it to the Bow River near Deerfoot Trail, defusing its intensity to nearly normal levels.

The cost will be high—up to $400-million for the two bypass systems and another $430-million for the berm and dry-pond systems. Water experts estimate that to spare High River another flood like the one it experienced in 2013, the pond on the Highwood River will have to store about 150 million m3 of water—6.6 times the amount held in Calgary’s Glenmore Reservoir.

Referred to by some as the province’s Hurrican Sandy, the flood may mark the moment when Albertans acknowledge climate change.

Although the diversion plans have been greeted with enthusiasm in flood-prone areas, Pomeroy cautions that changing the contour of land in the foothills could have unexpected consequences downstream. Wildlife and wilderness groups have expressed similar concerns. And any breach in the dikes would compound the disaster, as happened in New Orleans during Hurricane Katrina.

And the diversion plan offers no protection for areas not now considered prone to flooding due to out-of-date or inadequate information. Where will the next flood hit unexpectedly? Where is the next Hampton Hills? Pomeroy, who studies how mountain snowpack is affected by things like climate change, fires, forestry practices and the mountain pine beetle, says the only solution lies in a comprehensive water-management strategy for the eastern slopes, which supply the rivers in Western Canada with 90 per cent of their water. His advice to future developers: “Stay off flood plains. If you can see water, run the other way.”

A great rush to higher ground is unlikely, however. The province offered to buy out 254 homeowners living in floodways, but a disappointing response prompted High River town council to threaten to expropriate the other homes. By the November 30 deadline, only 101 Albertans had expressed interest in the buyout program, which pays tax-assessment value for their homes, and only 46 offers had been accepted by the province. People who refuse to relocate will not receive money from the province’s disaster recovery programs if they’re flooded out in the future.

The province’s handling of the disaster has prompted criticism from opposition politicians. Wildrose leader Danielle Smith, MLA for the High River area, blames the government for failing to act on the 2006 Groeneveld report. “Millions of dollars in damage could have been avoided,” she says. Calgary Liberal MLA Dr. David Swann cites the province’s failure to address the long-term effects of climate change, which could include more spring runoff as well as more summer droughts. “The government doesn’t seem willing to take the kind of leadership and control over the most basic, foundational aspect of our province—water,” he says. NDP leader Brian Mason accuses the Conservatives of misplaced priorities. “They see real action on climate change threatening their plans for oil development and for coal-fired electricity,” he says.

Government officials haven’t fully explained why they didn’t act on the Groeneveld report. The former High River-area MLA said his Conservative colleagues simply lost interest over time. “We went for a year without a flood, and man that window shut quickly,” Groeneveld says. “What scares me is that once we get further away from the flood of 2013, we’ll lose that sense of urgency.”

The government’s critics say they won’t let that happen. Smith, who in the 2012 provincial election said the science of climate change is not settled, is a recent convert, partly because of the floods. “We have now had three 100-year floods in the past 20 years,” she says. “We have to assume that something has changed to make our area more vulnerable.” Groeneveld, who was also a climate-change skeptic, has changed his thinking as well. “There has to be something causing all these over-the-top storms,” he says.

Back in High River, work is being completed to double the capacity of the Highwood River in time for this year’s flood season, which is but weeks away. Dredging efforts have removed the equivalent of 22 Olympic-sized swimming pools of muck and sludge from the river bottom. The banks have been reinforced with rock to reduce erosion. The town’s signature CP Rail bridge, abandoned in 2010, has been removed and the river widened to reduce impediments. Earthen dikes protecting vulnerable areas, including Highway 498 north of town, are being raised by about a metre.

Over the winter, residents continued to trickle back into their homes after what many described as a frustrating battle with their insurance companies and the disaster recovery programs over who would pay what to fix the flood damage. In Hampton Hills a hand-printed sign on a damaged home reads: “This is not a flood plain”—a sarcastic dig at the area’s designation as a rebuild zone. Many would like to see the neighbourhood declared a floodway so they can sell their homes to the province and move.

“I think there are a lot of people who feel that way,” says Miguel Rodrigues, who plans to return to a rebuilt home later this spring. “If we had the choice, we wouldn’t be moving back.”

As she prepared to move back into her Hampton Hills home, Sara Bruinsma reflected on the day almost a year ago when she and her family were forced out. After helping flooded-out friends living closer to the river, they came home to find their three-year-old dream home underwater. “We never thought the water would reach this high up,” she says. “It was devastating.” By Christmas, only about one-third of Hampton Hills residents had returned.

The developer, Lansdowne Equity, has another 96 lots for sale in the area and also has plans for a 250-unit condominium. Don Sandford, president of development for the company, is frustrated by what he believes are onerous new barriers put on the company because of the flood. The town won’t let the developer proceed before new mitigation measures are in place—which Sandford says is costing $25,000 a week in interest on the company’s investment as well as lost time.

“We could be building on those lots right now and creating a thriving recovery,” he says. “We’re just as much a victim as anyone else. There was never any indication when we started in 2005 that this would ever flood. There was nothing in the area structure plan to indicate it was at risk. None of the information from the province suggested the area would be prone to flooding. And now we have a $30-million investment that we could have been working on over several months that has been stalled.”

The housing lots are among a number of developments slated for the Hampton Hills area that may now be in jeopardy. Alberta Environment is investigating why the area flooded and whether future development there should halt permanently.

Mayor Snodgrass says all development plans are being reconsidered as a matter of caution. “If we don’t learn from the lesson that has just been handed to us, I think it would be extremely irresponsible for me and anyone else to go ‘yeah, we’re still good’ and to keep on doing what we’ve been doing,” he says.

The 42-year-old first-term mayor, whose own house and funeral business were damaged in the flood, said High River is “crossing its fingers” that the higher dikes hold during the coming flood seasons. The long-term solution, he believes, are the proposed water-diversion projects, which could take a year or two to build even if they are fast tracked.

He admits that as a municipal politician and lifelong resident of High River, he has to share the blame for not keeping flood protection top of mind. “You can’t point the finger only at the province for being complacent,” he says. “I’ll tell you that I wasn’t paying much attention. We get to thinking that ‘we know floods, we know what we’re doing.’ ”

He’s paying attention now. “It was going to take an event like this to really get it triggered,” he says.

Larry Johnsrude is a long-time western Canadian journalist and frequent contributor to Alberta Views. He lives in Edmonton.