Lacking flood forecasting, NWT focuses on readiness
After last spring’s unprecedented flooding and in anticipation of the thaw to come, the GNWT on Tuesday announced plans to strengthen emergency preparedness.
Officials said they are trying to better inform residents about preparing for spring flooding. Emily King, a GNWT emergency management specialist, said the territory had “provided comprehensive guidance to communities.”
“An enhanced public information campaign is under way to provide residents with information on personal preparedness, risk and disaster assistance,” King said.
Late last month, Mayor of Fort Simpson Sean Whelly told Cabin Radio the village was finalizing its new emergency plan and, he stressed, trying to warn residents that the village “can’t do everything.”
An information sheet now circulating in Fort Simpson asks residents: “If Fort Simpson floods, what is my plan?”
The sheet walks residents through a flow chart of potential decisions. Of the seven available outcomes on the flow chart, two include staying at home, two include camping (at the “tent city” constructed last year if necessary), one involves staying with others on higher ground, and two result in temporarily moving elsewhere, either with or without GNWT assistance.
One resident writing to Cabin Radio, who said the flow chart arrived in her mailbox from the village, said: “If you look at the flow chart, it seems very clear that the village has no plans to help residents. Most choices lead to ‘I will procure my own basic needs.’ It really seems like the village is saying that residents are on their own.”
Whelly has said relying on village assistance in the event of another flood is “probably an unrealistic expectation.”
The mayor said last month: “One of the things we’ve learned is that it would be very difficult for the village to be prepared to a point where no one had to make arrangements on their own.”
The NWT’s Department of Municipal and Community Affairs believes the recent lifting of Covid-19 public health measures will provide increased capacity for evacuation to communities such as Yellowknife if another flood hits. Last year, evacuations were hampered by a lack of available space elsewhere, particularly with some hotels in use as isolation centres.
Maca thinks there is now also a clearer plan to help community leaders respond in cases of escalating emergency.
“The GNWT is applying lessons learned from last year,” said King.
Lack of flood forecasting
Applying data is another matter.
Since the 1970s, Canada has approached the issue of flooding primarily by attempting to minimize new builds in prone areas and offering flood forecasting.
Since then, forecasting and early-warning technology have become important tools across the country. Provincial systems from BC through Alberta, Saskatchewan, Manitoba, Ontario and Quebec to Newfoundland are able to predict, with increasing accuracy, what residents in vulnerable areas can expect.
In the NWT, however, residents depend on a flood watch system.
“We have a team of scientists, or hydrologists, as they’re called, to assess conditions in real time to support Maca in making decisions about emergencies,” said Nathen Richea, director of water management and monitoring for the GNWT.
“We do not have flood forecasting capabilities at this time.”
Asked if the GNWT planned to invest in flood forecasting, Richea said: “It is something that we’re looking at. The challenge is that ice jams are very difficult to predict.”
NWT hydrologist and flood modeller Ryan Connon said comparisons to other jurisdictions are inaccurate because a significant proportion of floods in the territory depend on the behaviour of ice breakup, which is difficult to model.
“The hesitancy [around forecasting] comes from just not being able to predict, this far in advance, whether there will be an ice jam,” said Connon. “That’s true for all north-flowing rivers, it’s not just in the NWT.”
An upcoming paper in the Journal of Hydrology describes “the complexity of ice jamming” as a phenomenon that hydrologists struggle to anticipate. “Despite the best efforts from the investigating hydrometric agency, the data can be difficult to interpret and unreliable,” that paper states.
But as far back as 1992, people in the north have been trying. That year, researchers in Hay River used a “first-generation ice jam flood forecasting procedure” to predict flood events with “reasonable success.” Their paper appeared in the Canadian Journal of Civil Engineering exactly 30 years ago. In the years since, a substantial body of work both in Hay River and around the world has steadily contributed to understanding of how ice jams form.
Richea said his department was working with federal agencies that have ice engineers and access to satellite imagery. “We use that information a lot, along with existing water levels and flow, to provide advice to Maca,” he said.
Flood and ice jam prediction in Canadian provinces and territories has long operated with limited resources. Some experts are calling for a national forecasting system that would give communities more accurate information and allow them to better prepare.
“We did muddle by before with our 20th-century climate and our relatively low population, but that’s simply not adequate for the types of extreme events we’re experiencing now,” hydrology expert John Pomeroy told Global News in 2019.
In the meantime, residents of communities along the Mackenzie River are being told to move hazardous materials and belongings out of harm’s way, turn off electrical and heating appliances if a flood may be on the way, and contact their insurance company to hear about their flood policy.
“In lieu of a flood prediction system, we operate based on the principle of planning for the worst, but certainly hoping for the best,” said King.
Meanwhile, the territory is asking Indigenous governments, flood-affected residents, businesses and first responders to weigh in on the NWT’s response to last year’s flood emergency. Feedback about your experience last year can be submitted online until April 28.