Wildfires in the northwestern US

August 29th, 2012 |
GOES-13 0.63 µm visible channel + 3.9 µm shortwave IR channel data (click image to play animation)

GOES-13 0.63 µm visible channel + 3.9 µm shortwave IR channel data (click image to play animation)

McIDAS images of GOES-13 0.63 µm visible channel data during the day and 3.9 µm shortwave IR data at night (above; click image to play animation) revealed a number of very large and dense smoke plumes from wildfires that were burning in parts of the northwestern US (primarily in Idaho) on 28 August29 August 2012. The GOES-13 satellite had been placed into Rapid Scan Operations (RSO) mode, providing images as frequently as very 5-10 minutes.

During the following overnight hours, AWIPS images of Suomi NPP VIIRS 0.8 µm Day/Night Band (DNB), 3.74 µm shortwave IR, and 11.45 µm IR data (below) demonstrated the value of the DNB providing a visible channel at night (under ideal conditions of illumination by ample moonlight). While the 11.45 µm IR image verified that there were some patches of meteorological cloud in the region, the majority of the bright features seen on the DNB image were thick airborne smoke.

Suomi NPP VIIRS 0.8 µm Day/night Band, 3.74 µm shortwave IR, and 11.45 µm IR window images

Suomi NPP VIIRS 0.8 µm Day/night Band, 3.74 µm shortwave IR, and 11.45 µm IR window images

An even closer view using McIDAS-V images of VIIRS 0.8 µm DNB and 4.05 µm shortwave IR data (below; images courtesy of William Straka, CIMSS) highlighted the Mustang Fire Complex smoke plume and “fire hot spots” (black to yellow to red color enhancement) at 08:32 UTC. This fire was particularly hot, producing pyrocumulus clouds even into the night-time hours. The hottest IR brightness temperature  in the red-enhanced region was 546.5 K (or  273.4 C,  524 F).

Suomi NPP 0.8 µm Day/Night Band, 3.73 µm shortwave IR, and 11.45 µm longwave IR images

Suomi NPP 0.8 µm Day/Night Band, 3.73 µm shortwave IR, and 11.45 µm longwave IR images

===== 31 August Update =====

A night-time image comparison of the VIIRS 0.8 µm Day/Night Band and the corresponding 3.74 µm shortwave IR (below) revealed areas of smoke that were trapped in some of the valleys of central Idaho at 09:34 UTC (3:34 AM local time) on 31 August 2012.

Suomi NPP VIIRS 0.8 µm Day/Night Band image + 3.74 µm shortwave IR image

Suomi NPP VIIRS 0.8 µm Day/Night Band image + 3.74 µm shortwave IR image

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