How the BC Wildfire Service predicts wildfire behaviour
By Abigail Popple, Local Journalism Initiative Reporter, RMG
BC Wildfire Service (BCWS) maintains a comprehensive dashboard of ongoing fires throughout the province, with information on the size of fires, whether they are expected to grow, and a colour-coded map of incidents throughout the province. To learn more about how the Service collects such a wide range of information in the heat of the moment, The Goat spoke with BCWS Predictive Services Specialist Andrew Simpson.
It all starts with the initial on-the-ground report, says Simpson. Fires can be reported through the BCWS app, or by calling *5555, and the BCWS makes note of any details offered in the report. Once the Service arrives at the scene, responders contribute photos and on-the-ground reports to get an idea of how the fire is behaving.
“One of the most valuable pieces of information is the images taken by our bird dogs – the planes that are up there,” Simpson said. “Even if we decide that fire is not a suitable target for an air tanker drop, there will still be a flyover with photos taken. Those photos are valuable information.”
Crews who are battling the fire on the ground also report their observations to the Service, but for bigger fires, a fire behaviour analyst is on-site to make predictions.
“That’s a true specialist in fire behaviour who is looking forward to what the fire may do,” Simpson said. “There’s two things we look at: ‘What’s the fire doing on the ground?’ And, ‘What are the fuel and weather conditions that could drive the fire behaviour?’”
Another factor influencing fire behaviour is terrain, Simpson added. This is an especially important consideration in mountainous regions like the Robson Valley.
“The very steep, dramatic topography can have dramatic effects on funneling winds,” says Simpson. “That’s where the observations of someone in the field… can be really useful in confirming – or not – what the forecasted winds are expected to be.”
Wind speed, topography, and fuel availability are all factors takin into account in a mathematical model called the Canadian Forest Fire Behaviour Prediction System, which the BCWS uses to create a forecast of fire behaviour.
“All our firefighters have basic training in this stuff,” Simpson said of the prediction system. “These days we have a Red Book, which is a handbook that sort of guides you through it… It just gives you tables to look up, for example, what the anticipated rate of spread might be on a fire in a particular fuel type with a particular amount of wind. We’ve also recently created apps that do the same thing – you move some dials on the app and it gives you the same outputs.”
The forecasts produced with this model are similar to weather forecasts, according to Simpson: they can give a reliable short-term prediction of a fire’s behaviour, but the forecast gets less reliable for longer-term predictions.
In addition to this mathematical model, the BCWS uses computer modeling programs to predict overall potential fire spread. The Service recently added a web-based application that automatically generates modelling for multiple fires in a landscape, according to Simpson.
“It’s just another tool. It’s not by any means the magic bullet that’s going to solve all our problems,” said Simpson. “But when things get busy, it does give us the ability to get the kinds of outputs that used to take quite a bit of time to develop.”
But even computers aren’t foolproof, and the prediction system – which Simpson says was devised decades ago – has its shortcomings. It wasn’t designed to factor in long-term drought, which much of B.C. has been facing over the past two years, and there’s the chance of human error if someone incorrectly identifies what the fire’s fuel source is.
“This is why, when we issue predictions, we never say, ‘This is what the fire is going to do.’ It’s, ‘This is what we think this fire has the potential to do,’” Simpson said. “It’s a bit of a science and a bit of an art.”
