Pyrocumulonimbus clouds produced by the Dixie Fire in California

July 19th, 2021 |

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

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

5-minute GOES-17 (GOES-West) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm), “Clean” Infrared Window (10.35 µm) and Fire Temperature RGB images (above) revealed that the Dixie Fire in northern California produced a pair of pyrocumulonimbus (pyroCb) clouds— denoted by cloud-top 10.35 µm infrared brightness temperatures of -40ºC or colder (shades of blue pixels) — late in the day on 19 July 2021. The maximum surface 3.9 µm brightness temperature sensed with this fire was 138.7ºC — which is the saturation temperature for the ABI Band 7 detectors.

Pyrocumulonimbus cloud produced by the Bootleg Fire in Oregon

July 14th, 2021 |

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

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

1-minute Mesoscale Domain Sector GOES-17 (GOES-West) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm), “Clean” Infrared Window (10.35 µm) and Fire Temperature RGB images (above) revealed that the Bootleg Fire in far southern Oregon produced a pyrocumulonimbus (pyroCb) cloud — denoted by cloud-top 10.35 µm infrared brightness temperatures of -40ºC and colder (darker blue pixels) — late in the day on 14 July 2021. The maximum surface 3.9 µm brightness temperature sensed with this fire was 138.7ºC — which is the saturation temperature for the ABI Band 7 detectors.

A plot of 00 UTC rawinsonde data from nearby Medford, Oregon (below) indicated that the -40ºC temperature closely corresponded to the height of the tropopause and the Most Unstable (MU) air parcel Equilibrium Level (EL).

Plot of 00 UTC rawinsonde data from Medford, Oregon [click to enlarge]

Plot of 00 UTC rawinsonde data from Medford, Oregon [click to enlarge]

On the following morning, signatures of the upper-tropospheric/lower-stratospheric smoke that was forced aloft by the pyroCb cloud could be seen arcing east-southeastward over parts of Idaho, Montana and Wyoming on GOES-17 Visible and Near-Infrared “Cirrus” (1.37 µm) images (below). The smoke signature in 1.37 µm images was not due to the plume being composed of ice particles; rather, the Cirrus imagery is also able to highlight the presence of particles that are highly effective at scattering sunlight (which includes ice crystals, dust, volcanic ash, smoke) — and the smoke signature was also further highlighted by a favorable forward scattering angle.

GOES-17 "Red" Visible (0.64 µm, top) and Near-Infrared "Cirrus" (1.37 µm, bottom) images [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm, top) and Near-Infrared “Cirrus” (1.37 µm, bottom) images [click to play animation | MP4]

Pyrocumulonimbus clouds over British Columbia and California

June 30th, 2021 |

GOES-17 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, middle) and “Clean” Infrared Window (10.35 µm, bottom) [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, middle) and “Clean” Infrared Window (10.35 µm, bottom) [click to play animation | MP4]

GOES-17 (GOES-West) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.35 µm) images (above) showed the explosive formation of large pyrocumulonimbus (pyroCb) clouds that were spawned by large wildfires in British Columbia, Canada on 30 June 2021. The 10.35 µm cloud-top infrared brightness temperatures rapidly cooled to the -50 to -60ºC range, easily surpassing the -40ºC pyroCb threshold — and pyroCb 3.9 µm cloud-top infrared brightness temperatures were warmer (darker shades of gray) than those of surrounding meteorological cumulonimbus clouds (due to the presence of smaller ice crystals and smoke particles, which were better reflectors of incoming solar radiation).

GOES-17 Fire Temperature RGB images (below) include surface reports plotted in yellow — note that the temperature reached 115ºF (46.1ºC) at Kamloops (CYKA), just southeast of the largest fire. In addition, farther to the southwest, surface observations at Lytton (CWLY) ceased as of 01 UTC (6 PM local time), as another wildfire began to destroy 90% of that town.

GOES-17 Fire Temperature RGB images, with surface reports plotted in yellow [click to play animation | MP4]

GOES-17 Fire Temperature RGB images, with surface reports plotted in yellow [click to play animation | MP4]

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GOES-17 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, middle) and “Clean” Infrared Window (10.35 µm, bottom) [click to play animation | MP4]

GOES-17 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, middle) and “Clean” Infrared Window (10.35 µm, bottom) [click to play animation | MP4]

On a smaller spatial and temporal scale, GOES-17 Visible, Shortwave Infrared and Infrared Window images (above) revealed the brief formation of a pyroCb that was produced by the Lava Fire in far northern California. A portion of the cloud top reached the -40ºC threshold (darker shades of blue) to qualify as a pyroCb.

Chemtool facility fire in Rockton, Illinois

June 14th, 2021 |

GOES-16 "Red Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), Fire Power (bottom left) and Fire Temperature (bottom right) [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), Fire Power (bottom left) and Fire Temperature (bottom right) [click to play animation | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm), Fire Power and Fire Temperature derived products (above) showed the dark black smoke plume and thermal signature of a fire from an explosion at the Lubrizon Corporation Chemtool facility at Rockton in far northern Illinois on 14 June 2021. The thick smoke plume obscured the satellite’s view of the fire point source much of the time, preventing the continuous derivation of Fire Power and Fire Temperature products (and masking the thermal anomaly in the Shortwave Infrared images).

However, a comparison of Shortwave Infrared images from GOES-17 (GOES-West) and GOES-16 (below) revealed that the western satellite’s viewing angle allowed the thermal anomaly of the fire source (hot black-enhanced pixel) to be seen for a longer time period — even after the dark smoke plume had become well established.

Shortwave Infrared (3.9 µm) images from GOES-17 (left) and GOES-16 (right) [click to play animation | MP4]

Shortwave Infrared (3.9 µm) images from GOES-17 (left) and GOES-16 (right) [click to play animation | MP4]

GOES-16 Near-Infrared “Vegetation” (0.86 µm) images with plots of pilot reports (below) indicated that the smoke existed at altitudes of 2500 to 3000 feet, but was not restricting the surface visibility at sites that were downwind of the fire.

GOES-16 Near-Infrared "Vegetation" (0.86 µm) image, with plots of pilot reports and airport ceilings and visibility [click to enlarge]

GOES-16 Near-Infrared “Vegetation” (0.86 µm) images, with plots of pilot reports (yellow) and airport ceilings and visibility (cyan) [click to enlarge]

Closer views of GOES-16 Near-Infrared “Vegetation” images created using Geo2Grid (below) showed the southward transport of dark smoke as the fire continued to burn into the afternoon hours.

GOES-16 Near-Infrared "Vegetation" (0.86 µm) images [click to play animation | MP4]

GOES-16 Near-Infrared “Vegetation” (0.86 µm) images (credit: Tim Schmit, NOAA/NESDIS) [click to play animation | MP4]

Due to the very dark character of this particular smoke plume, it showed up much better against the more reflective surface in 0.86 µm imagery (compared to 0.64 µm “Red” Visible imagery), as seen in the image toggle below.

GOES-16 "Red" Visible (0.64 µm) and Near-Infrared "Vegetation" (0.86 µm) images at 1516 UTC (credit: Tim Schmit, NOAA/NESDIS) [click to enlarge]

GOES-16 “Red” Visible (0.64 µm) and Near-Infrared “Vegetation” (0.86 µm) images at 1516 UTC (credit: Tim Schmit, NOAA/NESDIS) [click to enlarge]

The dark smoke plume was also evident in various GOES-16 RGB combinations, such as True Color, Day Land Cloud, and Day Snow Fog (below). True Color RGB images showed that the smoke eventually drifted over far western Indiana.

GOES-16 True Color RGB images [click to play animation | MP4]

GOES-16 True Color RGB images [click to play animation | MP4]

GOES-16 Day Land Cloud RGB images [click to play animation | MP4]

GOES-16 Day Land Cloud RGB images [click to play animation | MP4]

GOES-16 Day Snow Fog RGB images [click to play animation | MP4]

GOES-16 Day Snow Fog RGB images (credit: Tim Schmit/NOAA/NESDIS) [click to play animation | MP4]