VIIRS Day/Night Band Observations of the Minnesota/Ontario Wildfires
Friend of the Blog Patrick Ayd, Science Operations Officer at NWS Duluth, passed on this interesting observation from the morning of 15 July 2026. The ongoing wildfires in Minnesota and Ontario, which we discussed in a blog post a few days ago, show up amazingly well when looking at the VIIRS Day/Night Band (DNB). The view below shows a string of brilliant blotches stretching across the middle of the image. Compare these bright spots to the city lights of metro Winnipeg (center of the left edge), Fargo (lower-left corner) or Duluth (western tip of Lake Superior). These are clearly some very large areas aflame.
To further convince ourselves that these are fires, let’s do a quick comparison to the 3.9 micron channel from the GOES-19 (GOES East) Advanced Baseline Imager. We use that latter channel for fire detection due to its extreme sensitivity to hot spots. Below is a slider that allows you to toggle back and forth between the low-earth orbiting VIIRS and the GOES ABI images. The dark spots indicate where active fires are, while the most intense fires have colors associated with them. You can see how the 3.9 micron fire spots line up perfectly with the bright spots in the middle of the DNB image, but the bright spots associated with the cities have no counterpart in the 3.9 micron imagery. In fact, you can even see an advantage of the VIIRS view: there are some locations right on the US/Canada border where smoke or clouds are obscuring the thermal signal of the fire but the visible brightness still shines through. The moon phase was new at this time and therefore was not illuminating the clouds.
As a bonus, here’s an animation for the GOES Fire Temperature RGB showing just how widespread (and hot!) these fires are. This product is available from SSEC’s Real Earth.
Starting now and continuing over the next few days, the smoke from these fires is going to impact large swaths of the continental United States. Stay tuned to the CIMSS Satellite Blog for more on that topic. Thanks, Patrick, for bringing this interesting satellite view to our attention!