Manitoba and Ontario Wildfires
Earlier this week, wildfires ignited and rapidly spread throughout the Canadian provinces of eastern Manitoba, and western Ontario, that led to numerous evacuations, several structures destroyed and fatalities. The high temporal resolution of the GOES-19 nighttime and daytime data (every 5-minutes), observed the initiation and the spread of the fires throughout a ~2 day timeframe. The GOES-19 ABI 3.9 um detected the first fire at night, seen in white pixels at ~6Z, 12 May 2025, located northeast of Selkirk, Manitoba. The other fires initiated to the east (and southeast) later that day and into 13 May 2025. Notice that several fires exhibit white pixels (warm brightness temperatures) that then transition to red pixels. The fire hotspots became so intense that the satellite sensor saturated, producing the red pixels. Clouds exhibit colder brightness temperatures and pass over the scene intermittently and can be seen in black and blue-green colors.
GOES-19 ABI 3.9 um from 0541Z, 12 May 2025 to 1000Z, 14 May 2025
On 13 May 2025, a few of the fires exhibited extreme fire behavior that led to rapid fire spread and the development of pyrocumulus (PyroCu) and pyrocumulonimbus clouds (PyroCb). Four overpasses from the JPSS VIIRS Fire Temperature RGB captured the PyroCb from the largest fire in eastern Manitoba, where liquid water clouds are depicted in blue and ice clouds in green. Note, the RGB is mainly used to observe fires in a qualitative way, where warm, very warm, hot, and intense fires are seen in red, orange, yellow, and white pixels, respectively. By 1953Z, 13 May 2025, the most intense fires were seen on the eastern and northern flanks of the two largest fires: the most northern fire that produced the PyroCb and the narrow fire located in western Ontario.
VIIRS Fire Temperature RGB imagery overpasses from 1744Z-1953Z, 13 May 2025
Nighttime visible imagery that is uniquely available on JPSS satellites and not on GOES, highlights the emitted lights from the fires, showing another way to view the areal extent of the fires at 750-m spatial resolution. The imagery also captured the nighttime fire smoke that advects to the north/northeast. Forecasters can utilize the VIIRS Near-Constant Contrast (NCC) product to identify fire smoke at night, since smoke and aerosols are challenging to detect in the infrared channels.
VIIRS NCC during the early morning hours of 13 and 14 May 2025