PyroCb in Wyoming

| August 15, 2016
GOES-15 Visible (top), Shortwave Infrared (middle) and Infrared Window (bottom) images [click to play animation]

GOES-15 Visible (top), Shortwave Infrared (middle) and Infrared Window (bottom) images [click to play animation]

A pyroCb cloud developed from the Maple Fire in far northwestern Wyoming during the late afternoon hours on 15 August 2016; GOES-15 (GOES-West) 0.63 µm Visible, 3.9 µm Shortwave Infrared and 10.7 µm Infrared Window images (above; also available as an MP4) showed the fire hot spot (red pixels on the 3.9 µm images) and the pyroCb cloud (shades of green to yellow on the 10.7 µm images) as it drifted southward then southwestward over far eastern Idaho by 0200 UTC on 16 August.

After sunset, GOES-15 3.9 µm Shortwave Infrared and 10.7 µm Infrared Window images (below; also available as an MP4) showed a gradual decrease in the intensity and areal coverage of the 3.9 µm fire hot spot, along with a continued cooling trend of the 10.7 µm pyroCb cloud-top IR brightness temperatures (which reached -49º C at 0341 and 0345 UTC).

GOES-15 Shortwave Infrared (top) and Infrared Window (bottom) images [click to play animation]

GOES-15 Shortwave Infrared (top) and Infrared Window (bottom) images [click to play animation]

A 4-panel composite of NOAA-18 images at 0146 UTC on 16 August (below; courtesy of Rene Servranckx) depicted a minimum cloud-top IR brightness temperature of -55.5º C, which corresponds to an altitude of 11.5 km according to the 00 UTC Riverton, Wyoming rawinsonde data.

NOAA-18 Visible (upper left), Shortwave Infrared (upper right), Infrared Window (lower left) and false-color RGB composite (lower right) images [click to enlarge]

NOAA-18 Visible (upper left), Shortwave Infrared (upper right), Infrared Window (lower left) and false-color RGB composite (lower right) images [click to enlarge]

PyroCb in Colorado

| July 28, 2016

On 27 July a pyroCb formed  from the Beaver Creek  Fire in Colorado. GOES-15 detected the smoke plumes and pyroCu cloud, as well as the fire hot spot. The pyroCb (40.9º N, 106.6º W) formed around 21:30 UTC .  Starting at 23:30 UTC on 27 July, the animation below (also available as an MP4) )shows GOES-15 (GOES-West) 0.63 µm visible (left) and 3.9 µm shortwave IR (right) . In the shortwave IR images, the red pixels indicate very hot IR brightness temperatures exhibited by the fire source regions.

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

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

Since GOES-15 has a lower resolution the brightness temperatures appeared warmer.A 1-km resolution NOAA-18 image at 00:24 UTC on 28 July (below; courtesy of René Servranckx) showed the cloud-top IR brightness temperature of the pyroCb to be -40.4º C (green color enhancement).

NOAA-18 AVHRR 0.64 µm visible (top left), 3.7 µm shortwave IR (top right), 10.8 µm IR window (bottom left) and false-color RGB composite image (bottom right).

NOAA-18 AVHRR 0.64 µm visible (top left), 3.7 µm shortwave IR (top right), 10.8 µm IR window (bottom left) and false-color RGB composite image (bottom right).

Multiple PyroCbs from Lava Mountain Fire in Wyoming

| July 25, 2016

On 25 July a pyroCb formed  from the Lava Mountain Fire in Wyoming. GOES-15 detected the smoke plumes and pyroCu cloud, as well as the fire hot spot. The pyroCb (43.6º N, 109.9º W) formed around 21:30 UTC .  Starting at 20:30 UTC on 25 July, the animation below (also available as an MP4) )shows GOES-15 (GOES-West) 0.63 µm visible (left) and 3.9 µm shortwave IR (right) . In the shortwave IR images, the red pixels indicate very hot IR brightness temperatures exhibited by the fire source regions.

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

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

In addition, using GOES-15 10.7 μm IR channel the cloud-top IR brightness temperature could be found. The animation below, starting at 22:00 UTC on 25 July, shows the brightness temperature for the pyroCu was  -32ºC around 23:45 UTC (dark blue color enhancement).

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

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

A 1-km resolution NOAA-19 image at 22:07 UTC (below; courtesy of René Servranckx)showed the cloud-top IR brightness temperature of the pyroCu to be -39.7º C (blue color enhancement).

NOAA-19 AVHRR 0.64 µm visible (top left), 3,7 µm shortwave IR (top right), 10.8 µm IR window (bottom left) and false-color RGB composite image (bottom right).

NOAA-19 AVHRR 0.64 µm visible (top left), 3.7 µm shortwave IR (top right), 10.8 µm IR window (bottom left) and false-color RGB composite image (bottom right).

However, this pyroCu was found to be a pyroCb using AVHRR 12.0 µm IR imagery. At 22:04 UTC this pyroCu reached pyroCb status by having a brightness temperature of -40º C. Shown on the image below as a green color enhancement.

AVHRR 12.0 µm IR image

AVHRR 12.0 µm IR image

On 26 July this fire produced another pyroCb. Suomi NPP VIIRS was used to show the brightness temperature (11.45 µm) and provide visible (0.64 µm) imagery. The image below shows the pyroCb reaching -49 º C  (green color enhancement) at 19:05 UTC.

Suomi NPP VIIRS Visible (0.64 μm) and Infrared Window (11.45 μm) images

Suomi NPP VIIRS Visible (0.64 μm) and Infrared Window (11.45 μm) images (click to animate)

OMPS Aerosol Index images below (courtesy of Colin Seftor) show the transport of smoke on 26 July. The maximum AI index was found to be 5.1 at 43.5 N 109W around 20:47 UTC (center image). This is near the fire that produced the pyroCb.

OMPS Aerosol Index image on 26 July

OMPS Aerosol Index image on 26 July

PyroCu in Wyoming

| July 18, 2016

On 18 July a pyroCu formed in Wyoming. GOES-15 detected the smoke plumes and pyroCu cloud, as well as the fire hot spot. The pyroCu (43.2º N, 110.5º W) formed from the Cliff Creek Fire around 21:00 UTC .  Starting at 20:30 UTC on 18 July, the animation below (also available as an MP4) )shows GOES-15 (GOES-West) 0.63 µm visible (left) and 3.9 µm shortwave IR (right). In the shortwave IR images, the red pixels indicate very hot IR brightness temperatures exhibited by the fire source regions.

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

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

A 1-km resolution NOAA-18 image at 21:46 UTC (below; courtesy of René Servranckx)showed the cloud-top IR brightness temperature of the pyroCu to be -30º C (dark blue color enhancement).

NOAA-18 AVHRR 0.64 µm visible (top left), 3,7 µm shortwave IR (top right), 10.8 µm IR window (bottom left) and false-color RGB composite image (bottom right). [click to enlarge]

NOAA-18 AVHRR 0.64 µm visible (top left), 3,7 µm shortwave IR (top right), 10.8 µm IR window (bottom left) and false-color RGB composite image (bottom right).

Suomi NPP OMPS Aerosol Index images from 19 July (below, courtesy of Colin Seftor) showed that the max AI index to be 4.6 at 45.29 N 103.39 W at 19:38 UTC. This is just east of the pyroCu and is conduce to the movement of the smoke in the animations above.

Suomi NPP OMPS Aerosol Index images

Suomi NPP OMPS Aerosol Index images

Two PyroCbs in Alaska

| July 15, 2016

On 15 July two pyroCbs formed in the interior of Alaska. GOES-15 detected the smoke plumes and pyroCb clouds, as well as the fire hot spots. The first pyroCb (65.8º N, 155.5º W) formed from the Dulbi Flats fire around 1:30 UTC . The second pyroCb (66.6º N, 153.8ºW ) formed from the Hog Fire, also around 1:30 UTC.  Starting at 21:00 UTC on 14 July, the animation below (also available as an MP4) )shows GOES-15 (GOES-West) 0.63 µm visible (top), 3.9 µm shortwave IR (middle) and 10.7 µm IR window images (bottom). In the shortwave IR images, the red pixels indicate very hot IR brightness temperatures exhibited by the fire source regions.

GOES-15 0.63 µm visible (top), 3.9 µ shortwave IR (middle) and IR window (10.7 µm) images [click to play animation]

GOES-15 0.63 µm visible (top), 3.9 µ shortwave IR (middle) and IR window (10.7 µm) images [click to play animation]

A 1-km resolution NOAA-18 image at 03:07 UTC (below; courtesy of René Servranckx) showed the cloud-top IR brightness temperature for the first pyroCb to be -50.2º C (yellow color enhancement) and the second pyroCb to be -48.3º C (dark green color enhancement).

NOAA-18 AVHRR 0.64 µm visible (top left), 3,7 µm shortwave IR (top right), 10.8 µm IR window (bottom left) and false-color RGB composite image (bottom right). [click to enlarge]

NOAA-18 AVHRR 0.64 µm visible (top left), 3,7 µm shortwave IR (top right), 10.8 µm IR window (bottom left) and false-color RGB composite image (bottom right). [click to enlarge]

On the following morning, a Suomi NPP VIIRS Day/Night Band (0.7 μm) image (below) provided a good view of the smoke plume, which had drifted eastward as far as the Alaska/Yukon border. Numerous fire hot spots were still seen on the corresponding VIIRS shortwave IR (3.74 μm) image (yellow to red color enhancement); note how there was no signature of the smoke plume on the VIIRS IR Window (11.45 μm) image, since smoke is transparent to thermal radiation at that wavelength.

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

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

Later in the day, Suomi NPP OMPS Aerosol Index (AI) values within the smoke plume feature (below; OMPS data courtesy of Colin Seftor) were as high as 8.0 (67.35ºN, 140.52ºW at 21:01:42 UTC) and 6.0 (66.96º N, 139.16º W at 22:42:33 UTC).

Suomi NPP OMPS Aerosol Index [click to enlarge]

Suomi NPP OMPS Aerosol Index [click to enlarge]

An overpass of the CALIPSO satellite after 13 UTC provided CALIOP data showing a portion of the smoke plume aloft, which exhibited high values of attenuated backscatter and low values of depolarization ratio (below).

CALIPSO CALOIP attenuated backscatter and depolarization data; Alaska pyroCb smoke plume aloft indicated by arrow [click to enlarge]

CALIPSO CALOIP attenuated backscatter and depolarization data; Alaska pyroCb smoke plume aloft indicated by arrow [click to enlarge]

===== 16 July Update =====

Suomi NPP OMPS Aerosol Index images from 16 July (below) showed that smoke from the Alaska pyroCbs continued to drift eastward across the Yukon and Northwest Territories regions of Canada.

Suomi NPP OMPS Aerosol Index images [click to enlarge]

Suomi NPP OMPS Aerosol Index images [click to enlarge]

PyroCb in Colorado

| July 10, 2016

On 10 July 2016 a pyroCb formed in association with the Hayden Pass fire in central Colorado. Both GOES-15 (GOES-West) and GOES-13 (GOES-East) detected the smoke plume and pyroCb cloud, as well as the fire hot spot. The pyroCb (38.3 N 105.8 W) occurred at around 22:30 UTC. Starting at 20:00 UTC on 10 July, the animations below show visible (.63 μm) in the top panels, shortwave IR (3.9 μm) in the middle, and IR Window (10.7 µm) in the bottom panels (click images to play animation). In the shortwave IR images the red pixels indicate very hot IR brightness temperatures exhibited by the fire source region.

GOES-15 (GOES-West) visible (top), shortwave IR (middle), and IR Window (bottom) images [click to play animation]

GOES-15 (GOES-West) visible (top), shortwave IR (middle), and IR Window (bottom) images [click to play animation]

GOES-13 (GOES-East) visible (top), shortwave IR (middle), and IR Window (bottom) images [click to play animation]

GOES-13 (GOES-East) visible (top), shortwave IR (middle), and IR Window (bottom) images [click to play animation]

Usually such pyroCb clouds are detectable by GOES satellites, with the criteria that they exhibit an IR Window (10.7 µm) cloud-top brightness temperature of -40º C or colder. However, in this case the 4-km GOES IR resolution was not sufficient to detect a brightness temperature colder than -20ºC. To classify this as a true pyroCb, 1-km resolution POES imagery was used. The NOAA-18 4-panel image below (courtesy of Rene Servanckx) shows a pyroCb cloud-top IR brightness temperature of -44.6ºC at 00:35 UTC on 11 July, which is indicated by a green color enhancement on the bottom left panel.

POES 1-km resolution images (upper left: 0.64 µm visible;upper right: 3.8 µm shortwave IR; lower left: 10.8 µm IR window; lower right: false-color RGB composite)

POES 1-km resolution images (upper left: 0.64 µm visible;upper right: 3.8 µm shortwave IR; lower left: 10.8 µm IR window; lower right: false-color RGB composite)

As the fire continued to burn into the subsequent nighttime hours, a comparison of Suomi NPP VIIRS shortwave infrared (3.74 µm) and Day/Night Band (0.7 µm) images at 08:59 UTC or 2:29 am local time on 11 July (below) showed the large hot spot (black to yellow to red color enhancement) as well as the bright glow of the large Hayden Pass fire (located in the lower center portion of the images); in addition, similar signatures of smaller fires burning northwest of Boulder (station identifier KBJC) and near/along the Colorado/Wyoming border could be seen.

Suomi NPP VIIRS shortwave infrared (3.74 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

Suomi NPP VIIRS shortwave infrared (3.74 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

OMPS Aerosol Index images below (courtesy of Colin Seftor) show the transport of smoke on 11 July. The maximum AI index was found to be 4.3 at 45.4 N 98.9 W (over northern South Dakota) around 18:48 UTC (center image). This is far northeast of the original Colorado pyroCb.

OMPS Aerosol Index image on 11 July

OMPS Aerosol Index image on 11 July

Due to a favorable sun/satellite forward scattering geometry, the east-northeastward transport of the smoke pall from the 10 July flare-up of the Hayden Pass fire was also evident on the following morning (11 July) GOES-15 visible images (below), with the hazy signature of smoke aloft drifting over parts of Kansas, Nebraska and South Dakota.

GOES-15 visible (0.63 um) images [click to play animation]

GOES-15 visible (0.63 um) images [click to play animation]