CIMSSPyroCb

PyroCb event in Northern California

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]
On August 11, 2014 a fire in northern California produced a pyroCb detected by GOES-15 0.63 µm visible channel and 3.9 µm shortwave IR channel images (above; click image to play animation) around 21:15 UTC located near 41º North and 123º West rapidly drifting northwest in the direction as the surrounding convection.  On the shortwave IR images (right panel), the red pixel enhancement shows when the fire hot spot reaches a IR brightness temperature of 338.3 K.

The corresponding GOES-15 10.7 µm IR channel images (below; click to play animation) indicated that the pyroCb cloud feature displayed a minimum IR brightness temperature value of -43.9º C around 21:00 UTC.  As the pyroCb developed, the cloud top continued to get colder reaching temperatures as cold as -55º C (approximately).

GOES-15 10.7 µm IR images [click to play animation]
GOES-15 10.7 µm IR images [click to play animation]

PyroCb at the South Fork fire complex in Oregon

GOES-15 (left panels) and GOES-13 (right panels) 0.63 µm visible channel and 3.9 µm shortwave IR channel images [click to play animation]
GOES-15 (left panels) and GOES-13 (right panels) 0.63 µm visible channel and 3.9 µm shortwave IR channel images [click to play animation]
The South Fork fire complex had been burning since being started by lightning on 31 July 2014 (InciWeb), and a pyroCb was seen to develop late in the day on 09 August 2014. A 4-panel comparison of GOES-15 (GOES-West) and GOES-13 (GOES-East) 0.63 µm visible channel and 3.9 µm shortwave IR channel images (above; click image to play animation; also available as an MP4 movie file) showed that there was a fire hot spot flare-up around 22:00 UTC (red pixels on the shortwave IR images), with the rapid development of the pyroCb cloud beginning around 23:45 UTC.

The corresponding GOES-15 and GOES-13 10.7 µm IR channel images (below; click image to play animation; also available as an MP4 movie file) revealed that cloud-top IR brightness temperatures of the pyroCb cloud became colder than -40º C (brighter green color enhancement) after 00:15 UTC; the coldest pyroCb cloud-top IR brightness temperature was -43.4º C on the 01:30 UTC GOES-15 R image.

GOES-15 (top) and GOES-13 (bottom) 10.7 µm IR channel images [click to play animation]
GOES-15 (top) and GOES-13 (bottom) 10.7 µm IR channel images [click to play animation]
Using the 00 UTC 10 August rawinsonde data from Salem, Oregon (below), the -40 to -43º C cloud-top IR brightness temperatures roughly corresponded to altitudes around 10-10.5 km (pressure levels of 280 to 254 hPa). The presence of northeasterly winds in the upper troposphere explained the southwestward drift of the pyroCb cloud. The tropopause was at a height of 13 km (178 hPa), at a temperature of -61.7º C.

Salen, Oregon rawinsonde data at 00 UTC on 10 August
Salen, Oregon rawinsonde data at 00 UTC on 10 August

NOAA ARL HYSPLIT model forecast trajectories initialized at the location of the first -40º C cloud-top  IR brightness temperatures (below) suggested an anticyclonic transport path that would bring the high-altitude smoke back northward over Oregon and Washington within 72 hours.

HYSPLIT model forward trajectories
HYSPLIT model forward trajectories

During the following overnight hours, a comparison of Suomi NPP VIIRS 3.74 µm shortwave IR and 0.7 µm Day/Night Band images at 09:49 UTC or 2:49 am local time (below) showed the hot spots (yellow to red color enhancement on the shortwave IR image) and the bright glow of the fires on the “visible image at night” Day/Night Band.

Suomi NPP VIIRS 3.74 µm shortwave IR and 0.7 µm Day/Night Band images
Suomi NPP VIIRS 3.74 µm shortwave IR and 0.7 µm Day/Night Band images

PyroCb by Great Slave Lake in the Northwest Territories

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]
On August 5, 2014 one of the fires surrounding the Great Slave Lake in the Northwest Territories, Canada produced a pyroCb detected by GOES-15 0.63 µm visible channel and 3.9 µm shortwave IR channel images (above; click image to play animation) around 20:00 UTC located near 60.5º North and 115º West, then rapidly drifting west as it develops.  At that time the fire source hot spot on the shortwave IR image (right panel) showed an IR brightness temperature of 338.3 K (red enhancement).

GOES-15 10.7 µm IR images [click to play animation]
GOES-15 10.7 µm IR images [click to play animation]
The corresponding GOES-15 10.7 µm IR channel images (above; click to play animation) indicated that the pyroCb cloud feature displayed a minimum IR brightness temperature value of -43.9º C at 20:00 UTC.  As the pyroCb developed, the cloud top continued to get colder and, therefore, higher up in the atmosphere.

The Aqua MODIS image (below) taken at 20:20 UTC shows the pyroCb in it’s very early stages of development.  The red pixels are hot spot enhancements, very similar to the enhancements on the shortwave IR imagery, indicating where the fires are located around Great Slave Lake.

MODIS true-color image of Great Slave Lake with a red-pixel enhancement over the fires.
Aqua MODIS true-color image of Great Slave Lake with a red-pixel enhancement over the fires.

 

PyroCb multi-day outbreak event along the California and Oregon border

On July 30, 2014, a lightning strike started the Oregon Gulch Fire, part of the Beaver Complex of fires, becoming an extremely active fire due to the very dry conditions in this part of the country.  As these fires grew, another thunderstorm system passed through northern California on August 1, 2014 with over 1,000 lightning strikes recorded; this system started a series of fires in that area that quickly spread with the help of the even drier conditions compared to southern Oregon.  These two areas of fires created several pyroCbs starting August 1 to August 3, 2014.

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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]
On August 1st, 2014 at 02:45 UTC, the Beaver Complex Fire produced a pyroCb just north of the California/Oregon border near Ashland, Oregon. GOES-15 0.63 µm visible channel and 3.9 µm shortwave IR channel images (above; click image to play animation) showed that the pyroCb cloud feature became well-defined starting 02:00 UTC, drifting rapidly northward into a line of thunderstorms. At that time the fire source hot spot (located near 41º North, 122.2º West) exhibited an IR brightness temperature of 338.3 K (red enhancement).

The corresponding GOES-15 10.7 µm IR channel images (below; click to play animation) indicated that the pyroCb cloud feature displayed a minimum IR brightness temperature value of -43.9º C starting 01:00 UTC and quickly grew in height based on the colder temperatures indicated by the IR brightness temperature.

GOES-15 10.7 µm IR images [click to play animation]
GOES-15 10.7 µm IR images [click to play animation]
During the development of this pyroCb, the 173rd Fighter Wing of the Oregon Air National Guard flew F-15 Eagle fighter jets over the area and captured some incredible pictures of the pyroCb around 02:00 UTC or 8:00pm local time. The GOES-15 visible and shortwave IR image is a still frame taken about the same time as the photos were taken from the cockpit of the F-15 Eagle.

GOES-15 0.63 µm visible (left) and 3.9 µm shortwave IR (right) image at 02:00 UTC on August 1, 2014.
GOES-15 0.63 µm visible (left) and 3.9 µm shortwave IR (right) image at 02:00 UTC on August 1, 2014.

 

An F-15 Eagles from the 173rd Fighter Wing, Oregon Air National in the foreground of a pyroCb produced from the Oregon Gulch Fire. (Photo Credit: Jim “Hazy” Haseltine, HIGH-G Productions)
An F-15 Eagles from the 173rd Fighter Wing, Oregon Air National in the foreground of a pyroCb produced from the Beaver Complex Fire. (Photo Credit: Jim “Hazy” Haseltine, HIGH-G Productions)
An F-15 Eagles from the 173rd Fighter Wing, Oregon Air National in the foreground of a pyroCb produced from the Oregon Gulch Fire. (Photo Credit: Jim “Hazy” Haseltine, HIGH-G Productions)
An F-15 Eagles from the 173rd Fighter Wing, Oregon Air National in the foreground of a pyroCb produced from the Beaver Complex Fire. (Photo Credit: Jim “Hazy” Haseltine, HIGH-G Productions)
An F-15 Eagles from the 173rd Fighter Wing, Oregon Air National in the foreground of a pyroCb produced from the Oregon Gulch Fire. (Photo Credit: Jim “Hazy” Haseltine, HIGH-G Productions)
An F-15 Eagles from the 173rd Fighter Wing, Oregon Air National in the foreground of a pyroCb produced from the Beaver Complex Fire. (Photo Credit: Jim “Hazy” Haseltine, HIGH-G Productions)

 

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On Friday August 1, two more pyroCbs manifested in the same region.  GOES-15 visible channel and IR channel images (below) show the first pyroCb developed around 23:00 UTC located near 41º North, 121.1º West and the second event around 01:00 UTC on August 2 located near 42º North, 122º West.

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]
 

The GOES-15 10.7 µm IR channel images (below; click to play animation, also available as an MP4 move file) during the same time frame as the visible and shortwave IR show that these two pyroCb features display a  minimum IR brightness temperature value of -43.9º C at 23:30 UTC  located near 41º North, 121.1º West and 01:30 UTC located near 42º North, 122º West.

GOES-15 10.7 µm IR images [click to play animation]
GOES-15 10.7 µm IR images [click to play animation]

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The fires in Northern California and Southern Oregon on August 2, 2014. (Photo Credit: Wildfire Today)
The fires in Northern California and Southern Oregon on August 2, 2014. (Photo Credit: Wildfire Today)
Saturday, August 2 was an extremely active day for fires burning in Southern Oregon and Northern California.  These fires produced an astounding five pyroCbs seen in the GOES-15 visible channel and shortwave IR channel images (below; click to play animation).  The first pyroCb manifested from the Beaver Complex Fire around 21:00 UTC located right on the California/Oregon Border (42º North, 122.3º West).  The Bald Fire in California spawned the second pyroCb around 22:00 UTC near 41.7º North and 122º West. The third pyroCb event was produced from the KNF Beaver Fire just south of the California/Oregon border (located near 42º North, 123º West) around 23:00 UTC.  The Eiller Fire, just southwest of the Bald Fire, developed the fourth pyroCb around 00:30 UTC on August 3 approximately located at 41º North and 121.5º West.  The final pyroCb was generated from the Little Deer fire (located near 41º North, 121.5º West) around 01:45 UTC August 3.

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]
 

GOES-15 10.7 µm IR images [click to play animation]
GOES-15 10.7 µm IR images [click to play animation]
The corresponding GOES-15 10.7 µm IR channel images (above; click to play animation) show the pyroCb cloud features for all five events starting around 21:00 UTC.  All these events happened quite rapidly and the GOES-15 10.7 µm IR channel images do an excellent job showing on pyroCb spawning after another after another.

Here is a night-time comparison of AWIPS images of Suomi NPP VIIRS 3.74 µm shortwave IR and 0.7 µm Day/Night Band data (below) at  10:21 UTC (or 3:21 AM local time) on August 3.  The shortwave IR image “hot spots” (black to yellow to red enhancement) shows these fires continuing to burn through the night.

Suomi NPP VIIRS 3.74 µm shortwave IR and 0.7 µm Day/Night Band images
Suomi NPP VIIRS 3.74 µm shortwave IR and 0.7 µm Day/Night Band images

 

PyroCb event in British Columbia

GOES-15 0.63 µm visible (left) and 3.9 µm shortwave IR (right) images

On August 2nd, 2014 a pyroCb was detected in British Columbia by GOES-15 0.63 µm visible channel and 3.9 µm shortwave IR channel images (above). The pyroCb occurred around 02:45 UTC, located near 53º North and 125º West. The shortwave IR images (right panel) shows several hot spots (black to red pixels), but only the southern most hot spot forms into a pyroCb. The red pixel enhancement shows when the fires reach an IR brightness temperature of 338.3 K.  The pyroCb moves north after formation and starts to dissipate. This is seen most easily in the GOES-15 10.7 µm IR channel images (below).  

GOES-15 10.7 µm IR images

The upper air sounding at Port Hardy (below) shows that the winds present in the upper troposphere were indeed moving northward at 15-20 knots.

Port Hardy, BC sounding at 00 UTC on 02 August

The Terra MODIS image (below) was taken at 10:00 UTC and shows the aftermath of the pyroCb event. The red pixel enhancements, like the shortwave IR images, show the location of fires.

Terra MODIS true-color image of the British Columbia fires with a red-pixel enhancement over the fires.

PyroCb in the Northwest Territories of Canada

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]
On the evening of 29 July 2014, a small pyroCb cloud was produced by a one of the ongoing fires in the Northwest Territories of Canada. GOES-15 0.63 µm visible channel and 3.9 µm shortwave IR channel images (above; click image to play animation; also available as an MP4 movie file) showed that the pyroCb cloud feature became well-defined on the 00:30 UTC (30 July) image, drifting rapidly northeastward. At that time the fire source hot spot (located near 61.5º North, 121.7º West) exhibited an IR brightness temperature of 338.3 K (red enhancement).

The corresponding GOES-15 10.7 µm IR channel images (below; click to play animation; also available as an MP4 movie file) indicated that the pyroCb cloud feature displayed a minimum IR brightness temperature value of -43.9º C at 03:30 UTC.

GOES-15 10.7 µm IR images [click to play animation]
GOES-15 10.7 µm IR images [click to play animation]
The -43.9º C GOES-15 IR brightness temperature corresponded to an altitude of 23,662 feet (7215 meters) on the Fort Smith, Northwest Territories rawinsonde profile at 00 UTC on 30 July (below).

Fort Smith, Northwest Territories rawinsonde data (00 UTC 30 July)
Fort Smith, Northwest Territories rawinsonde data (00 UTC 30 July)

NOAA ARL HYSPLIT forward trajectories initiated at the location of the coldest GOES-15 cloud-top IR brightness temperature (at altitudes of 6, 7, and 8 km) suggested that the high-altitude smoke would be transported eastward, then northeastward during the subsequent 36 hours (below).

HYSPLIT model forward trajectories at altitudes of 6, 7, and 8 km
HYSPLIT model forward trajectories at altitudes of 6, 7, and 8 km

A composite of Suomi NPP VIIRS true-color swaths during the daytime on 30 July (below) did show an area of dense smoke over much of western Nunavut, which was in agreement  with the transport shown by the HYSPLIT trajectories. The VIIRS image also showed large amounts of smoke being drawn southward along the back side of the deep 500 hPa low centered over James Bay.

Suomi NPP VIIRS true-color composite image for 30 July
Suomi NPP VIIRS true-color composite image for 30 July