By Scott Bachmeier •
GOES-18 (GOES-West) Dust RGB images (above) showed a plume of resuspended volcanic ash (brighter shades of pink) from the 1912 Novarupta-Katmai eruption in Alaska, which was being transported offshore across the Shelikof Strait (and Buoy 46077, where the peak wind gusts were 31 knots) toward Kodiak Island on 10 October 2023. Surface ash within the Valley Of Ten Thousand Smokes was being lofted by a burst of strong northwesterly winds — a toggle between the 1200 UTC Dust RGB image and Topography (below) highlighted the valleys associated with the ash source region. As the plume of resuspended ash moved over the northern portion of Kodiak Island, the Kodiak Airport (PADQ) began to report Volcanic Ash (VA) at 1900 UTC (below) — and the ash plume briefly restricted the surface visibility to 8 miles at 2200 UTC. While a signature of the plume was also evident in GOES-18 Ash RGB imagery, it was more obvious in the Dust RGB (below) — both RGBs use the same spectral bands and spectral band differences, but the individual RGB components are scaled differently (so an examination of both is advised, in order to determine which RGB is best to track an ash-related feature). GOES-18 daytime True Color RGB + Nighttime Microphysics RGB images from the CSPP GeoSphere site (below) provided another view of the resuspended ash plume.Categories: GOES-18, Red-Green-Blue (RGB) images