CIMSSPyroCb

Another PyroCb in Saskatchewan

On 24 and 25 June the fire named 15BN-BRADY produced a pyroCb that was reported on (see blog post). On 26 June this fire produced another pyroCb at 22:00 UTC at 56.8 N 109.3 W. GOES-15 detected the smoke plume and pyroCb cloud, as well as the fire hot spot. Starting at 21:00 UTC on 26 June, 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.

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]
Furthermore, using GOES-15 10.7 μm IR channel the cloud-top IR brightness temperature could be found. The animation below, starting at 21:00 UTC on 26 June, shows the brightness temperature of this pyroCb reaching -55.1ºC (yellow color enhancement) around 23:45 UTC.

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

 

Multiple PyroCbs in Alberta

On 26 June there were a reported two pyroCb in Alberta just west of Lake Athabaska. The first was at 58.7 N 113 W  formed around 19:15 UTC. The second was at 59.3 N 11.7 W formed around 21:15 UTC. GOES-15 detected the smoke plumes and pyroCb clouds, as well as the fire hot spot. Starting at 19:30 UTC on 26 June, 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.

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]
Below is a magnified version of the loop above to clearly show the development of the pyroCbs.

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]
 Also, using GOES-15 10.7 μm IR channel the cloud-top IR brightness temperature could be found. The animation below, starting at 19:30 UTC on 26 June, shows the brightness temperature of the first pyroCb reaching -53.5ºC (yellow color enhancement) around 21:15 UTC on 26 June. In addition, the loop shows the second pyroCb reaching -54.7ºC around 22:00 UTC (indicated by yellow/orange color enhancement).

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

 

Two PyroCbs in Yukon

On 25 June a pyroCb formed at 23:45 UTC in Yukon (63.1 N 136.1 W). Also, another pyroCb formed on 26 June at 02:15 UTC at 62.8 N 137.8 W. GOES-15 detected the smoke plume and pyroCb cloud, as well as the fire hot spot. Starting at 21:45 UTC on 25 June, 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.

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]
Also, using GOES-15 10.7 μm IR channel the cloud-top IR brightness temperature could be found. The animation below, starting at 21:45 UTC on 25 June, shows the brightness temperature of the first pyroCb reaching -56.2ºC (yellow color enhancement) around 01:45 UTC on 26 June. From the Whitehorse Sounding this put the cloud top at 11 km. In addition, the loop shows the second pyroCb reaching around -50ºC around 4:30 UTC (indicated by yellow color enhancement).

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

On 26 June OMPS Aerosol Index (AI) images were useful to see the transport of the smoke. From the AI image (below; courtesy of Colin Seftor and Rene), it can be seen that the smoke was being transported eastward. Region 1 tracks back to the Yukon pyroCb that is discussed above. While region 2 is from fires in the Northwest Territories.

OMPS Aerosol Index image on 26 June (click to enlarge)
OMPS Aerosol Index image on 26 June (click to enlarge)

PyroCb in Northwest Territories

On 25 June there was a pyroCb that was produced at 23:30 UTC in the Northwest Territories (62.3 N 117.3 W). GOES-15 detected the smoke plume and pyroCb cloud, as well as the fire hot spot. Starting at 19:00 UTC on 26 June, 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.

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]
 Furthermore, using GOES-15 10.7 μm IR channel the cloud-top IR brightness temperature could be found. The animation below, starting at 19:00 UTC on 26 June, shows the brightness temperature of this pyroCb reaching -50.6ºC (yellow color enhancement) around 00:00 UTC on 26 June.

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

PyroCb in Saskatchewan

According to the Canadian Wildland Fire Information System on 07 June a fire called 15BN-BRADY started. By 24 June it was reported that a pyroCb was produced from this fire around 23:00 UTC in Saskatchewan (56.8 N 109.3 W). By 25 June the fire has grown to 7,115 hectares. GOES-15 detected the smoke plume and pyroCb cloud, as well as the fire hot spot. Starting at 21:00 UTC on 24 June, 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.

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]
Also, using GOES-15 10.7 μm IR channel the cloud-top IR brightness temperature could be found. The animation below, starting at 21:00 UTC on 24 June, shows the brightness temperature of this pyroCb reaching -59.2ºC (lime green/yellow color enhancement) around 00:30 UTC on 25 June.

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

Another PyroCb in Alaska

On 20 June according to the Alaska Interagency Coordination Center the Blair Fire started in the interior of Alaska (south of Fairbanks) at 64.3º N 147.3º W. On 24 June at 20:15 UTC a pyroCb formed from this fire. GOES-15 detected the smoke plume and pyroCb cloud, as well as the fire hot spot. Starting at 19:00 UTC on 24 June, 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 darker black to red pixels indicate very hot IR brightness temperatures exhibited by the fire source region.

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]
Also, using GOES-15 10.7 μm IR channel imagery the cloud-top IR brightness temperature could be determined. The animation below, starting at 19:00 UTC on 24 June, shows the brightness temperature of this pyroCb reaching -53.6ºC (lime green/yellow color enhancement) around 21:45 UTC.

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

A timely overpass of the Suomi NPP satellite provided a good view of the pyroCb cloud very soon after its formation — a comparison of 20:18 UTC VIIRS 0.64 µm visible channel, 3.74 µm shortwave IR channel, and 11.45 µm IR channel images is shown below. On the visible image, the tall pyroCb cloud casts a shadow onto the dense layer of smoke below; the fire hot spot (black to yellow to red pixels) can be seen along the southeastern edge of the cloud; the minimum cloud-top IR brightness temperature was -56º C, which corresponded to an altitude of approximately 10.8 km (using data from the 00 UTC Fairbanks sounding). At the time of the VIIRS images, smoke was reducing the surface visibility at Fairbanks (PAFA) to 3/4 of a mile, and to the west-northwest at Tanana (PATA) the occasional fall of wildfire ash was being reported at the surface.

Suomi NPP VIIRS 0.64 µm visible, 3.74 µm shortwave IR, and 11.45 µm IR images
Suomi NPP VIIRS 0.64 µm visible, 3.74 µm shortwave IR, and 11.45 µm IR images

A sequence of daily Suomi NPP VIIRS true-color image composites from 18 June to 24 June (below) showed a dramatic increase in the areal coverage of dense wildfire smoke over Alaska during that period. A post on the Wildfire Today site mentioned the high number of lightning strikes that had occurred over the region in recent days, with a record  of over 14,000 lightning strikes in a single day on 21 June. A closer view of the 24 June VIIRS true-color image with an overlay of AVHRR-detected fire hot spots can be seen here. Due to the dense smoke , the Air Quality Index at Fairbanks on 24 June was 242 (on a scale of 0-500), placing it in the “Very Unhealthy” category.

Daily composites of Suomi NPP VIIRS true-color images during the 18 June - 24 June 2015 period
Daily composites of Suomi NPP VIIRS true-color images during the 18 June – 24 June 2015 period

Regarding the “smoke vortex” seen over northern Alaska on the 24 June VIIRS images above, GOES-15 0.63 µm visible channel images (below; click to play animation) showed the development and motion of this feature during the day. A pair of fires seemed to intensify in the southern foothills of the Brooks Range, north-northeast of Fort Yukon (PFYU), as the vortex passed — perhaps this was a boundary layer feature that helped to increase surface winds in its wake.

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

On 24 June OMPS Aerosol Index (AI) images were useful to see the transport of the smoke. From the AI image (below; courtesy of Colin Seftor and Rene), it can be seen that the smoke was being transported eastward. Region 1 has a max value of 3.6 which is consistent with the time and location of the max value of 7.5 on 23 June. These values both trace back to the region where five pyroCbs developed in Alaska between 21:45 UTC on 22 June and 07:30 UTC 23 June. Region 2 has a max value of 2.9 and is from the northern British Columbia pyrocb. Region 3 has a max value of 7.2 and is from the pyroCb produced by the Blair fire that is discussed above. Region 4 has the highest value on the map at 7.8 but can’t be traced directly back to a source, most likely from the numerous fires burning close by.

OMPS Aerosol Index image on 24 June (click to enlarge)
OMPS Aerosol Index image on 24 June (click to enlarge)