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Pyrocumulonimbus cloud spawned by the Creek Fire in California

By Scott Bachmeier •

GOES-17 “Red” Visible (0.64 µm, top left), GOES-17 Shortwave Infrared (3.9 µm, top right), GOES-17 Fire Temperature RGB + GLM Flash Extent Density(bottom left) and

GOES-17 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), Fire Temperature RGB + GLM Flash Extent Density (bottom left) and “Clean” Infrared Window (10.35 µm, bottom right) [click to play animation | MP4]

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm), GOES-17 Shortwave Infrared (3.9 µm), Fire Temperature Red-Green-Blue (RGB) + GLM Flash Extent Density (FED) and “Clean” Infrared Window (10.35 µm) images (above) showed the formation of a pyrocumulonimbus (pyroCb) cloud created by the Creek Fire in Central California on 05 September 2020. The appearance of a few brief GLM FED pixels (2026 UTC | 2117 UTC) indicated that this pyroCb cloud was producing lightning; the coldest cloud-top infrared brightness temperatures were -56.3ºC. The pyroCb developed after the Creek Fire made an explosive run to the north — and the pyroCb also spawned 3 “fire tornadoes”, two of which were rated EF2 and EF1 (SPC Storm Reports | Wildfire Today).

A comparison of time-matched Infrared Window images of the Creek Fire pyrocumulonimbus cloud from Suomi NPP (SNPP) and GOES-17 (below) highlighted differences in spatial resolution — 375-m with SNPP, vs 2-km (at satellite sub-point) with GOES-17 — and parallax displacement inherent with GOES-17 imagery at that location (17 km for a 15.2-km tall cloud top). The coldest cloud-top infrared brightness temperatures were -71.0ºC with SNPP, vs -55.5ºC with GOES-17. Identical color enhancements were applied to both images.

Infrared Window images from Suomi NPP and GOES-17 [click to enlarge]

Infrared Window images from Suomi NPP (11.45 µm) and GOES-17 (10.35 µm) [click to enlarge]

Several hours later, a nighttime comparison of Suomi NPP VIIRS Day/Night Band (0.7 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images of the Creek Fire at 0935 UTC or 2:35 am PDT (below) showed the bright glow of the large fire, with several small but very hot fires continuing to burn along its periphery — and a few pyrocumulus clouds were developing along the western/southwestern edge. Along the northeastern edge of the fire signature, outlined in blue, is the Mammoth Pool Reservoir — where over 200 people needed to be airlifted from a campground after the only exit road was cut off by the fast-moving fire (media report).

Suomi NPP VIIRS Day/Night Band (0.7 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images

Suomi NPP VIIRS Day/Night Band (0.7 µm), Shortwave Infrared (3.74 µm) and Infrared Window (11.45 µm) images [click to enlarge]


Categories: Fire detection, GLM, GOES-17, Lightning, Red-Green-Blue (RGB) images, Suomi NPP, VIIRS