Carr Fire pyrocumulonimbus in California

July 27th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and Shortwave Infrared (3.9 µm, right) images [click to play MP4 animation]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) showed the large thermal anomaly or “hot spot” (cluster of red pixels) associated with the Carr Fire in northern California as it produced a pyrocumulonimbus (pyroCb) cloud during the afternoon hours on 27 July 2018. A 30-meter resolution Landsat-8 False Color image from the previous day showed the large size of the burn scar; extreme fire behavior on 27 July caused the Carr Fire to quickly increase in size and move closer to Redding CA, and also produce the pyroCb.

Another view using GOES-16 “Red” Visible, Shortwave Infrared, “Clean” Infrared Window (10.3 µm) and the Cloud Top Temperature product (below) showed the pyroCb cloud as it drifted rapidly northeast over Nevada and Oregon, along with a second (albeit smaller) pyroCb cloud which developed around 0130 UTC. One standard parameter used for defining a pyroCb cloud is a minimum cloud-top longwave infrared brightness temperature of -40ºC (ensuring complete glaciation) — and in this case with 1-minute imagery, the multi-spectral Cloud Top Temperature (CTT) product (FAQ) indicated that the pyroCb cloud reached the -40ºC threshold 19 minutes earlier than the 10.3 µm infrared imagery. From that point forward, the CTT product was consistently at least 5-10ºC colder than the 10.3 µm brightness temperature; the CTT product eventually displayed a minimum value of -53.9ºC over northeastern California. Even as the 10.3 µm brightness temperature began to rapidly warm after about 0100 UTC, the CTT product continued to display values in the -45 to -50ºC range (shades of green) which allowed for unambiguous tracking of the pyroCb.

GOES-16 "Red" Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), "Clean" Infrared Window (10.3 µm, bottom left) and Cloud Top Temperature product (bottom right) [click to play MP4 animation]

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), “Clean” Infrared Window (10.3 µm, bottom left) and Cloud Top Temperature product (bottom right) [click to play MP4 animation]

In the case of the second (smaller) pyroCb cloud that formed from the Carr Fire after 0130 UTC, the 10.3 µm brightness temperature failed to reach the -40ºC threshold, while the CTT product again displayed values in the -45 to -50ºC range. The coldest CTT value of -53.9ºC (seen with the initial pyroCb) roughly corresponded to an altitude of 12.5 km or 41,000 feet according to 00 UTC rawinsonde data from Reno, Nevada (below). Strong upper-tropospheric winds of 80-90 knots rapidly transported the pyroCb anvil northeastward.

Plot of 00 UTC rawinsonde data from Reno, Nevada [click to enlarge]

Plot of 00 UTC rawinsonde data from Reno, Nevada [click to enlarge]

Cranston Fire pyrocumulonimbus

July 25th, 2018 |

GOES-16

GOES-16 “Red” Visible (0.64 µm, left) and Shortwave Infrared (3.9 µm, right) images, with hourly plots of surface reports [click to play animation | MP4]

GOES-16 (GOES-East) “Red” Visible (0.64 µm) and Shortwave Infrared (3.9 µm) images (above) showed the smoke and pyrocumulus clouds as well as the thermal anomaly or “hot spot” (red pixels) associated with the Cranston Fire — located in the center of the images — which started southwest of Palm Springs, California (KPSP) around 1852 UTC or 11:52 am PDT on 25 July 2018. The large areas of red seen on the Shortwave Infrared images early in the animation were signatures of very hot sandy soil surfaces of the southern California deserts. Note the very warm air temperatures seen across the region; Palm Springs had an afternoon high of 116ºF, and Thermal KTRM had a high of 119ºF (farther inland, Death Valley had a high of 127ºF).

A slightly different view — with the fire located in the lower left corner, southwest of KPSP — using GOES-16 “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.3 µm) images (below) revealed that the fire actually produced 3 distinct pulses of pyroCumulonimbus (pyroCb) cloud, where the 10.3 µm cloud-top infrared brightness temperature reached or exceeded the -40ºC threshold (lime green enhancement). Three specific times that these separate pyroCb clouds were evident were 2102 UTC, 2147 UTC and 2312 UTC.

GOES-16 "Red" Visible (0.64 µm, left), Shortwave Infrared (3.9 µm, center) and "Clean" Infrared Window (10.3) images, with 4-letter airport identifiers plotted in yellow [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm, left), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.3 µm, right) images, with 4-letter airport identifiers plotted in yellow [click to play animation | MP4]

Another view of the pyroCb pulses was provided by a 4-panel view of GOES-16 “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm), “Clean” Infrared Window (10.3 µm) and Cloud Top Phase (below). The coldest 10.3 µm cloud-top infrared brightness temperatures were -55ºC as the primary pyroCb anvil drifted northeastward toward the California/Nevada border.

GOES-16 "Red" Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), "Clean" Infrared Window (10.3 µm, bottom left) and Cloud Top Phase (bottom right) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), “Clean” Infrared Window (10.3 µm, bottom left) and Cloud Top Phase (bottom right) images [click to play animation | MP4]

There was also substantial lightning observed with these pyroCb clouds:


Below is a timelapse video of the first 8 hours of the fire, which shows the pyroCb evolution at the end.

Timelapse of Cranston Fire [click to play YouTube video]

Timelapse of Cranston Fire [click to play YouTube video]

===== 26 July Update =====

GOES-16 "Red" Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), "Clean" Infrared Window (10.3 µm, bottom left) and Fire Temperature (bottom right) images [click to play animation | MP4]

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), “Clean” Infrared Window (10.3 µm, bottom left) and Fire Temperature (bottom right) images [click to play animation | MP4]

Another pyroCb was produced by the Cranston Fire on 26 July, as shown by GOES-16 “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm), “Clean” Infrared Window (10.3 µm) and Fire Temperature images (above). Similar to the previous day, there appeared to be 2 pulses of pyroCb formation — with cloud-top infrared brightness temperatures cooling to -44ºC. Pyrocumulus from the smaller Ribbon Fire (just southeast of the Cranston Fire) could also be seen.

Wildfires in Greece

July 24th, 2018 |

Suomi NPP VIIRS Shortwave Infrared (3.75 µm), Near-Infrared (1.61 and 2.25 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.75 µm), Near-Infrared (1.61 and 2.25 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

Suomi NPP VIIRS Shortwave Infrared (3.75 µm), Near-Infrared (1.61 and 2.25 µm) and Day/Night Band (0.7 µm) images (above) showed thermal signatures and the bright glow of wildfires in the Athens, Greece area at 0005 UTC or 3:05 am local time on 24 July 2018. The 2 largest fires were burning in the vicinity of Kineta and Mati.

Similar images from an overpass of the NOAA-20 satellite 50 minutes later are shown below.

NOAA-20 Shortwave Infrared (3.75 µm), Near-Infrared (1.61 and 2.25 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

NOAA-20 Shortwave Infrared (3.75 µm), Near-Infrared (1.61 and 2.25 µm) and Day/Night Band (0.7 µm) images [click to enlarge]

Over 70 deaths have resulted from these fast-moving wildfires, which were driven by strong winds (below).

Time series of surface observations at Athens, Greece [click to enlarge]

Time series of surface observations at Athens, Greece [click to enlarge]

VIIRS images courtesy of William Straka, CIMSS.

Ferguson Fire in California forms a pyrocumulonimbus cloud

July 15th, 2018 |
GOES-16

GOES-16 “Red” Visible (0.64 µm, left), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.3 µm, right) images [click to play MP4 animation]

* GOES-17 images shown here are preliminary and non-operational *

The Ferguson Fire in central California produced a pyrocumulonimbus (pyroCb) cloud during the afternoon hours on 15 July 2018. GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.3 µm) images (above) showed that the high-altitude portion of the pyroCb cloud then drifted northeastward toward the California/Nevada border, where cloud-top infrared brightness temperatures cooled to near -55ºC (orange enhancement) as it crossed the border around 0005 UTC on 16 July.

A comparison of Visible images from GOES-15 (0.63 µm), GOES-17 (0.64 µm) and GOES-16 (0.64 µm) is shown below — with the imagery displayed in the native projection of each satellite. Images from GOES-16/17 are at 5-minute intervals, while images from GOES-15 are every 5-15 minutes depending on the operational scan schedule of that GOES-West satellite. GOES-17 was at its post-launch checkout position of 89.5ºW longitude, so it offered a more direct view of the pyroCb cloud.

Visible images from GOES-15 (0.63 µm, left), GOES-17 (0.64 µm, center) and GOES-16 (0.64 µm, right) [click to play animation]

Visible images from GOES-15 (0.63 µm, left), GOES-17 (0.64 µm, center) and GOES-16 (0.64 µm, right) [click to play animation]

A toggle between NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images (below) showed the pyroCb cloud southwest of the California/Nevada border (between Bridgeport KBAN and Mammoth KMMH) at 2327 UTC. In spite of a minimum cloud-top 10.8 µm infrared brightness temperature of -59ºC (red enhancement), note the darker (warmer) appearance of the cloud on the 3.7 µm image — this is due to reflection of solar radiation off the smaller ice particles of the pyroCb anvil. The -59ºC temperature roughly corresponded to an altitude of 13 km or 42.6 kft on the 00 UTC Reno, Nevada rawinsonde report (plot | data)

NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images [click to enlarge]

NOAA-19 Visible (0.63 µm), Shortwave Infrared (3.7 µm) and Infrared Window (10.8 µm) images [click to enlarge]

A time lapse of the pyroCb was created by Sierra Fire Watch (below).

Time lapse [click to play YouTube video]

Time lapse [click to play YouTube video]