The GNWT started updating the estimated hectares values more frequently so we decided to remove our estimate in favor of theirs.
We recently added our own estimated hectares affected statistic to the NWT Wildfire Tracker. Here’s a straightforward explanation of how we calculate the total area affected by fires within the boundaries of the Northwest Territories (NWT).
Our Process
Here’s a step-by-step look at how we determine the total fire-affected area within the NWT:
- Collecting Data:
- We start by gathering maps showing the areas affected by wildfires (fire perimeters) from the Canadian Wildland Fire Information System (CWFIS) and the boundaries of the NWT.
- Trimming to Boundaries:
- We adjust the fire perimeters so they fit exactly within the NWT boundary. This way, we only measure the part of the fire inside the NWT.
- Calculating the Area:
- We calculate the size of the fire-affected areas in hectares.
- We figure out what percentage of each fire’s area lies within the NWT boundary.
- Adjusting with Official Data:
- We combine our measurements with the original data from CWFIS to make our calculations even more accurate.
- Summing Up:
- We add up all the fire-affected areas within the NWT to get the total area.
Our estimate is not meant to undermine the GNWT’s (Government of the Northwest Territories) estimated hectares affected by wildfires. The GNWT’s data is more fine-grained and designed to track smaller fires that might not be detected by our method. However, the GNWT’s data is updated less frequently than the estimated perimeters from CWFIS.
Our fire perimeters are based on low-resolution satellite imagery from sources like AVHRR, MODIS, and VIIRS. These sources identify “hotspots”—pixels with high infrared intensity indicative of fire. These hotspots are processed to exclude industrial heat sources, leaving only vegetation fires, and then aggregated to form estimated fire perimeters. Due to the low resolution, these estimates are best suited for large fires and should be considered rough approximations. They may miss smaller fires or fires obscured by clouds.
Our method provides a good estimate but relies on lower resolution data that does not capture high-precision perimeters. The GNWT’s data, while more detailed, is less frequently updated.
Our method for calculating the total area affected by fires within the NWT is designed to provide a reliable estimate. By combining maps, measurements, and official data, we aim to offer useful information. However, it is important to remember that this is an estimation based on low-resolution data and may not capture smaller fires or precise perimeters. For more detailed data, the GNWT’s reports, although updated less frequently, provide more granular information on wildfire impacts.