CIMSS Satellite Blog

GOES-16 Near-Infrared “Snow/Ice” (1.61 µm) images [click to play animation | MP4]

GOES-16 (GOES-East) Near-Infrared “Snow/Ice” (1.61 µm) images (above) revealed a darker swath — oriented southwest to northeast, from central South Dakota to central Minnesota — highlighting areas which received an accrual of ice (from freezing rain/drizzle) during a 30 December – 31 December 2018 mixed precipitation event (surface analyses). Light to moderate Freezing Rain was reported at Watertown SD (KATY) for 3.5 consecutive hours (plot | text).

Snow and ice are efficient absorbers of radiation at the 1.61 µm wavelength, making them appear darker on the Snow/Ice imagery — and since ice absorbs more strongly than snow, it appears as the darkest shades of gray/black. Strong northerly winds in the wake of the precipitation event then swept the residual ice-crusted snow cover clear of any new snowfall.

A higher spatial resolution view using VIIRS Near-Infrared “Snow/Ice” (1.61 µm) images from NOAA-20 (at 1839 UTC) and Suomi NPP (at 1931 UTC) is shown below. The darkest areas on the Snow/Ice images appeared to be over the southern/western portion of Deuel County in South Dakota and much of Chippewa County in Minnesota.

VIIRS Near-Infrared “Snow/Ice” (1.61 µm) images from NOAA-20 (at 1839 UTC) and Suomi NPP (at 1931 UTC) [click to enlarge]

from CIMSS Satellite Blog http://cimss.ssec.wisc.edu/goes/blog/archives/31237