Record-breaking warm temperatures and dry conditions meant considerable fire danger across western Canada this week. Several wildfires did indeed develop in British Columbia, and were captured by GOES and JPSS satellites on 29 June 2021. Further, Pyrocumulonimbus clouds developed in association with the wildfire smoke plumes.
Three large wildfires developed on the northern edge of the GOES-West (5-min) PACUS sector, but well within the far northwest portion of the GOES-East CONUS sector. Of course, both the GOES-East and GOES-West full disk sectors included the wildfires. While GOES-West provided slightly better spatial detail (closer to satellite sub-point), the GOES-East imagery provided better temporal coverage (5-min vs 10-min) of the fire hot spots and the resulting smoke plumes and pyroCb, as well as a unique side angle view.
GOES-West Full Disk Geocolor imagery blended with the Fire Temperature RGB provides a nice overview of the event (Fig 1). The three wildfires (red to yellow) can be observed growing rapidly, eventually developing smoke plumes, and then pyrocu => pyrocb. A thunderstorm is captured in the scene to the southeast of the wildfires. This animation can be replicated in AWIPS.
The Natural Color Fire RGB, which can also be easily created in AWIPS, combines the SWIR, Veggie, and Red VIS bands to provide hot spot, smoke plume, and burn scar information in a single product (Fig 2).
Turning attention to the GOES-East 5-min imagery (from AWIPS), The same natural Color Fire RGB is created. Note that the southwestern-most fire is not as apparent in the GOES-West imagery due to clouds blocking the view from GOES-East. The GOES-West perspective, viewing from the other side of the clouds, had a clear view of the hot spot. This is another case that demonstrates the value in using both GOES satellites, if possible, especially in the presence of cloud cover. GLM flash grid (blue) is also included in the animation, and captured lightning associated with on of the pyrocb (more on this later).
Another useful animation combines VIS and IR imagery (sandwich) with the Fire Mask derived product to show information about active wildfire hotspots (yellow stationary blocks), smoke plumes, and pyrocb cloud top characteristics (cool to warm colors interpolated), in a single animation. GLM flash grid is again included. Cloud top IR brightness temperatures quickly cooled to below -40C, and reached to around -50C, with these pyrocb.
More on the GLM flashes! Figure 5 shows that both GOES-East (blue) and GOES-West (orange/yellow) detected the lightning flash (very near each other!) associated with the pyrocb at 0135 UTC. Recall, the flash centroid points in AWIPS (dots) are parallax corrected, while the gridded product, is not parallax corrected. Therefore, while the gridded product will match with the imagery (parallax displacement away from the satellite sub-point), the point product will be (more correctly) displaced toward the satellite subpoint (to the southwest in GOES-West, to the southeast in GOES-East), and match closer to other products such as ground based lightning data, radar, etc.
From JPSS, SNPP and NOAA-20 VIIRS imagery also captured the wildfires, in better (750 m and always near sub-point) spatial detail. Four passes were available over the fires during the day. The Fire Temperature RGB in Figure 6 captures the growth of the initial fire, while the fire to the southwest can be found in its infancy in the last image, prior to its appearance in GOES (~3/4″ above “06”).
Figure 6: Slide show showing SNPP and NOAA-20 VIIRS Fire Temperature RGB during the day on 29 June 2021.
Three nighttime VIIRS passes show the wildfires captured in the Day Night Band Near Constant Contrast product (Figure 7). The square root enhancement grayscale colormap is used, with the range expanded to capture more detail in the fires. The bright rings associated with the actively burning areas (surrounding already burned but dimmer area) are easily diagnosed in the images. The faint appearance of smoke can also be seen emanating from the fires.
Figure 7: Slide show showing SNPP and NOAA-20 VIIRS Day Night Band Near Constant Constant Contrast imagery during the early morning (ore-sunrise) hours on 30 June 2021.
The wildfires continued to grow and through day and into the evening on the 30th, with environmental conditions supporting the development of new wildfires. By late afternoon into the evening, GOES imagery revealed the redevelopment of pyrocb associated with the most intense wildfires and smoke plumes. Cloud tops cooled to less than -55C, strong thunderstorm signatures including overshooting tops and above anvil signature plumes were present. Once again, the Natural Color Fire RGB provided a complete view of the scene in a single RGB, including the wildfire hot spots, smoke plumes, and detailed storm top features. The development of shadows toward sunset allows the user to to identify the texture associated with these features much easier.
The three now larger wildfires from the previous night were again diagnosed in the VIIRS DNB NCC imagery (Fig 9).
Bill Line, NESDIS and CIRA