Possibility for a PyroCb in Southern California

Terra/Aqua MODIS and Suomi NPP VIIRS true-color images (click to enlarge)

Terra/Aqua MODIS and Suomi NPP VIIRS true-color images (click to enlarge)

On 17 June 2015 the Lake Fire fire started east of San Bernardino, California (34.1º N 117.3º W). On 18 June, the large smoke plume could be seen spreading eastward on true-color images from Terra/Aqua MODIS and Suomi NPP VIIRS (above). At 15:30 UTC on 18 June it was estimated that 10,000 acres had burned with a two day potential of 50,000 acres. There were not favorable conditions for firefighting, with winds out the southwest at 17 mph gusting up to 28 mph. This information and the photo below courtesy of Wildfire Today.

Photo of the Lake Fire at 20:15 UTC on 18 June (click to enlarge)

Photo of the Lake Fire at 20:15 UTC on 18 June (click to enlarge)

GOES-15 detects the smoke plume and hotspots from this fire. Starting at 13:00 UTC the animation below shows visible (.63 μm) on the left and shortwave IR (3.9 μm) on the right (click image to play animation). In the shortwave IR images the red pixels indicate very hot IR brightness temperatures exhibited by the fire source region. A closer view of the smoke plume can be seen this animation of GOES-15 visible images.

GOES-15 0.63 μm visible (left) and 3.9 μm shortwave IR (right) images (click to play animation)

GOES-15 0.63 μm visible (left) and 3.9 μm shortwave IR (right) images (click to play animation)

In addition, using GOES-15 10.7 μm IR channel images the cloud-top IR brightness temperature can be found. If the brightness temperature becomes colder than -40ºC it indicates that a pyroCb has formed. From the animation below, starting at 13:00 UTC, it is apparent that the clouds produced by this fire are not pyroCb, since the clouds produced never get colder than -20ºC.

GOES-15 10.7 μm IR image (click to play animation)

GOES-15 10.7 μm IR image (click to play animation)

It is interesting to note that a pilot report at 20:19 UTC indicated that the top of the smoke plume had reached an altitude of approximately  35,000 feet (below).

GOES-15 10.7 µm IR channel image, with surface observations and pilot reports (clic k to enlarge)

GOES-15 10.7 µm IR channel image, with surface observations and pilot reports (click to enlarge)

On 18 June OMPS AI Index images were used again to see the transport of the smoke. From the AI image (below; image courtesy of Colin Seftor), the smoke is moving eastward. On 18 June at 20:24 the max AI of 12.2 was at 33.87 N 115.55 W, which is just east of the original fire.

OMPS Aerosol Index images on 18 June (click to enlarge)

Taking advantage of the large forward scattering angle from the GOES-13 (GOES-East) satellite, the final daytime visible images (below; click image to play animation) revealed the large areal coverage of the smoke plume from the Lake Fire, which had spread over southern Utah, much of the northwestern half of Arizona, and even over northwestern Mexico. Smoke plumes from a few wildfires in Arizona could also be seen.

GOES-13 0.63 µm visible channel images (click to play animation)

GOES-13 0.63 µm visible channel images (click to play animation)

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