As the rain fell and waters rose in the days before last year’s floods, no one anticipated how devastating the damage would be. The Alberta floods destroyed homes, cars, roads and lives. With a recovery cost in the billions, the 2013 Alberta floods are the most expensive in Canada’s history.
Limiting flood damage requires accurate predications and effective planning, but even with some of the best data in the world, predicting floods isn’t easy, says Colleen Walford, a river flow forecaster with Alberta Environment and Sustainable Resource Development. “Weather models are calibrated on past events and when Mother Nature throws a large really dynamic event at us, the weather models aren’t necessarily set up to handle being able to predict the rain fall intensities that happened.”
Given weather’s penchant for the unexpected, Walford says Alberta added rainfall alarms to their forecasting network this year. The alarms capture rain and compare it to predicted levels. If the amounts pass a certain threshold, the alarm triggers a phone call to the person responsible for the area, waking them up if need be. But even with new technology in the field, the backbone of flood prediction remains accurate weather forecasts.
Walford says they need weather models to tell them three things to accurately predict potential floods: the total rainfall amount, the intensity of the rainfall throughout the storm and the timing of the most intense downpours. That information, combined with where storms will happen in relation to river basins, mostly comes from the federal government.
Michel Jean, the director general of weather and environmental operations at Environment Canada, says if the models predict the conditions for dangerous weather, they alert the province, letting it know the likelihood and location of the extreme weather. It’s then up to the provinces to run the data through their local models and decide whether to issue an alert.
Jean says though Canada’s weather modeling system is one of the best in world, there isn’t a national body responsible for flood prediction because it would be impossible for it to manage all the necessary local data. “The modeling they do is at a much finer level of detail than what we will ever be able to do with our numerical weather prediction models.” But he adds that not having a nationwide system has led to inconsistencies in the quality of monitoring in the provinces.
In the wake of last year’s floods in Alberta, a province with a good flood prediction system, Jean says they’re trying to make improvements across the country in order to mitigate flood damage. “We are looking for a more consistent approach to flood forecasting across the country,” he says. “Those discussions are ongoing, but we’re making good progress.”