Snow cover and ice accrual across the Upper Midwest

November 11th, 2020 |

GOES-16 “Red” Visible (0.64 µm), Near-Infrared

GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Snow/Ice” (1.61 µm) and Day Snow-Fog RGB images [click to play animation | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm), Near-Infrared “Snow/Ice” (1.61 µm) and Day Snow-Fog Red-Green-Blue (RGB) images (above) showed a broad swath of fresh snow cover across parts of Nebraska, South Dakota, Iowa, Minnesota, Wisconsin and Upper Michigan on 11 November 2020. The band of heavy snow developed northwest of an intensifying midlatitude cyclone on the previous day (surface analyses) — storm total snowfall amounts included 11 inches in Nebraska, 11 inches in Minnesota, 8 inches in South Dakota, 7.5 inches in Iowa and 6.8 inches in Wisconsin.

GOES-16 “Red” Visible (0.64 µm), Near-Infrared "Snow/Ice" (1.61 µm) and Day Snow-Fog RGB images at 1501 UTC [click to enlarge]

GOES-16 “Red” Visible (0.64 µm), Near-Infrared “Snow/Ice” (1.61 µm) and Day Snow-Fog RGB images at 1501 UTC [click to enlarge]

In a comparison of images at 1501 UTC (above), note the darker shades of gray/black on the 1.61 µm image and the darker shades of red on the RGB image along the southeastern edge of the heavy snow band — this highlighted areas where a significant accrual of ice resulted from freezing rain/drizzle. As seen in a plot of ABI Spectral Response Functions (below), snow and ice are efficient absorbers of radiation (and therefore exhibit a low relectance) at the 1.61 µm wavelength, making them appear darker on the Snow/Ice and RGB images — and since ice absorbs more strongly than snow, it appears as the darkest shades of gray/black (1.61 µm) or red (RGB).

Plots of Spectral Response Function for ABI Bands 1-5 [click to enlarge]

Plots of Spectral Response Function for ABI Bands 1-5 (credit: Mat Gunshor, CIMSS) [click to enlarge]