“Pyrobubbles” originating from fires in the northwestern US

GOES-15 0.63 µm visible channel images (click image to play animation)

GOES-15 0.63 µm visible channel images (click image to play animation)

Mike Fromm (NRL) coined the term “pyrobubbles”, and pointed out 3 examples that occured on 16 August 2013. We shall examine each of thse 3 cases using GOES-15 (GOES-West) imagery. The first pyrobubble originaled from a fire near the Idaho/Montana border; GOES-15 0.63 µm visible channel images (above; click image to play animation) showed the appearance of a distinct pyroCu cloud at 21:41 UTC, from which emanated a brief burst of smoke which moved rapidly eastward as it spread out over western Montana (moving over Helena KHLN around 01:00 UTC).

The corresponding GOES-15 10.7 µm IR channel images (below; click image to play animation) showed the smoke plume exhibited an IR brightness temperature of -20º C (cyan enhancement) near the fire source region at 22:00 UTC, reaching a minimum of -38º C (light green enhancement) over western Montana at 00:30 UTC.

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

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

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GOES-15 0.63 µm visible channel images (click image to play animation)

GOES-15 0.63 µm visible channel images (click image to play animation)

The second case occured farther south over southern Idaho; GOES-15 0.63 µm visible channel images (above; click image to play animation) revealed a well-defined pulse of pyroCu smoke which was ejected upward through the lower elevation smoke pall at 23:41 UTC.This pulse of smoke then spread out as it moved rapidly eastward across Idaho.

The corresponding GOES-15 10.7 µm IR channel images (below; click image to play animation) showed that this smoke feature first exhibited an IR brightness temperature of -20º C (cyan enhancement) at 23:00 UTC, reaching a minimum of -37º C at 00:30 UTC.

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

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

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GOES-15 0.63 µm visible channel images (click image to play animation)

GOES-15 0.63 µm visible channel images (click image to play animation)

The third event was over northern Utah; GOES-15 0.63 µm visible channel images (above; click image play animation) first showed the pyroCu-induced upward pulse of smoke just south of the Great Salt Lake at 22:30 UTC. Similar to the previous 2 events, this pulse of smoke then raced rapidly eastward away from the source region.

The corresponding GOES-15 10.7 µm IR channel images (below; click image to play animation) showed this smoke feature did not exibit IR brightness temperatures as cold as the other 2 cases — values between -20º C and -25º C were briefly seen from 23:00 to 23:30 UTC.

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

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

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