05/15/2026
⚡How can lightning strike, but a wildfire doesn't appear until days or even weeks later?
Think about a small chip in your car’s windshield. At first, it might seem minor and barely noticeable. But later conditions change, the temperature drops and you hit a bump in the road and that tiny chip suddenly spreads into a large crack.
Lightning can work in a similar way. A strike may leave behind heat deep in tree roots, stumps or underground organic material without immediately creating visible flames or smoke, especially if the storm also brought rain.
Then, days or weeks later, as conditions become hotter, drier and windier, that hidden heat can begin to spread and ignite nearby fuels, eventually becoming a visible wildfire. Areas with a higher Duff Moisture Code are more likely to sustain these holdover fires.
So, how do we know where to watch?
We use Environment and Climate Change Canada’s Canadian Lightning Detection Network (CLDN), for an instantaneous and constant feed of lightning data with information on the location, time, amperage and polarity of each lightning strike. We compare this data with radar and our weather network to see if nearby stations recorded any rainfall. We usually look for positively charged lightning strikes with no accompanying precipitation. Positive strikes typically have the highest amperage and likelihood of sparking new fires.
After a storm has moved through an area, we conduct air and/or ground patrols in known lightning pathways to look for smoke or heat. These patrols are timed for when smoke or heat from the strike are likely to be found. Ground patrols focus on smoke plumes and can be done by staff from areas with good visibility of the areas of concern, air patrols look for smoke plumes and may also use thermal imaging to locate heat signatures in the forest. Thermal imaging can be undertaken by hand-held devices on the ground, devices used by our staff in rotary- or fixed-wing aircraft and by commercial equipment installed on fixed-wing aircraft, satellites or unmanned aerial vehicles/drones.
Learn more about our predictive services unit: https://www2.gov.bc.ca/gov/content/safety/wildfire-status/prepare/predictive-services
