Plume of wildfire smoke from British ColumbiaGOES-17 (GOES-West) “Red” Visible (0.64 µm) and Low-level Water Vapor (7.3 µm) images (above) showed a northeasterly flow (model analyses) off the coast of British Columbia, Canada on 25 March 2019. Contained within this offshore flow was a hazy plume moving over Haida Gwaii and out across the eastern Pacific Ocean.
This aerosol plume was more easily seen in GOES-17 True Color Red-Green-Blue (RGB) images from the AOS site (below).In comparisons between VIIRS Visible (0.64 µm) and Day/Night Band (0.7 µm) from Suomi NPP at 2104 UTC and NOAA-20 at 2154 UTC (below), the portion of the plume where aerosols were most dense (and therefore more reflective) was better portrayed in the Day/Night Band images. Similarly, the portion of this plume having a higher aerosol concentration was highlighted using Terra MODIS Near-Infrared “Cirrus” (1.61 µm) imagery (below). The corresponding MODIS Water Vapor (6.7 µm) image showed that while the plume was generally contained within a ribbon of drier air, a narrow tongue of moisture existed within the core of the band of dry air. Both the VIIRS and the MODIS imagery indicated that the plume was passing over Sandspit (surface identifier CYZP), where the surface visibility briefly dropped to 7 miles at 21 UTC during a short period of northwesterly winds. A toggle between the 2015 UTC Suomi NPP VIIRS True Color RGB image and Aerosol Optical Depth product as viewed using RealEarth (below) also showed the plume was passing over station CYZP on Haida Gwaii. Note that there were a few VIIRS fire detection points (red dots) in central British Columbia — which suggests that this aerosol plume was likely smoke from biomass burning. Regarding the moisture gradient seen on the MODIS Water Vapor image, it is interesting to examine 3 adjacent closely-spaced NUCAPS soundings immediately south of CYZP (below). The Total Precipitable Water values increased from 0.18″ to 0.26″ within a distance of only 60 miles.