Re-suspended volcanic ash from the Novarupta volcano in Alaska
McIDAS images of GOES-15 Visible (0.63 µm) data (above) showed the hazy signature of a plume of re-suspended volcanic ash originating from the region of the Novarupta volcano in Alaska, moving southeastward over the Shelikof Strait toward Kodiak Island on 29 September 2014. The 1912 eruption of Novarupta left a very deep deposit of volcanic ash, which often gets lofted by strong winds in the early Autumn months before snowfall covers the ash (another example occurred on 22 September 2013). Surface winds gusted as high as 30 knots at regional reporting stations, with numerical models estimating terrain-enhanced winds as high as 40-50 knots over the Novarupta ash field.An AWIPS II image of POES AVHRR Visible (0.86 µm) data (below) showed the ash plume at 22:46 UTC; a pilot report at 22:45 UTC indicated that the top of the ash plume was between 4000 and 6000 feet above ground level.

POES AVHRR Visible (0.86 µm) image, with METAR surface reports and Pilot Reports (PIREPs) [click to enlarge]