Calf Canyon Fire produces a pyrocumulonimbus cloud

May 10th, 2022 |

GOES-16 “Red” Visible (0.64 µm, top left), Shortwave Infrared (3.9 µm, top right), Infrared Window (10.35 µm, bottom left) and Cloud Top Temperature derived product (bottom right) [click to play animated GIF | MP4]

1-minute Mesoscale Domain Sector GOES-16 (GOES-East) “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm), “Clean” Infrared Window (10.35 µm) and Cloud Top Temperature derived product images (above) showed that the northern portion of the Calf Canyon Fire/Hermits Peak Fire in New Mexico produced a pyrocumulonimbus (pyroCb) cloud on 10 May 2022. Extreme fire behavior was aided by surface wind gusts in the 42-64 mph range and very dry air within the boundary layer (along with very dry fuels from the ongoing drought); these large fires also burned very hot, with 3.9 µm Shortwave Infrared brightness temperatures reaching 138.71ºC — the saturation temperature of ABI Band 7 detectors. Coldest 10.35 µm cloud-top brightness temperatures exhibited by the pyroCb cloud were around -45ºC (lighter blue enhancement), with the Cloud Top Temperature product showing values as cold as -54ºC (red pixels).

In a comparison of NOAA-20 VIIRS True Color RGB, False Color RGB and Infrared Window (11.45 µm) images valid at 2057 UTC (below), the coldest cloud-top infrared brightness temperature was -59ºC. These images were acquired and processed using the Direct Broadcast ground station at SSEC/CIMSS.

NOAA-20 VIIRS True Color RGB, False Color RGB and Infrared Window (11.45 µm) images [click to enlarge]

During the preceding nighttime hours, a toggle between Suomi-NPP VIIRS Day/Night Band and Shortwave Infrared images valid at 0847 UTC or 2:47 am MDT (below) showed the bright emitted light and hot thermal signature of active fires along the periphery of the burn area — especially along the northern fire front, which eventually produced the pyroCb cloud.

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

An evolution of the recent New Mexico wildfires using a series of VIIRS Day/Night Band images is available at this blog post.

Day Night Band Imagery of fires in New Mexico

May 10th, 2022 |

The Day Night Band on the VIIRS sensor that flies on both Suomi NPP and NOAA-20 will view emitted light (or reflected moonlight) at night. The animation above (derived from imagery at the VIIRS Today website — from this sector, specifically) shows the light emissions from cities in New Mexico (click here to see the annotated first image with place names), and, notably, fires. Multiple fires are apparent in the animation. For example: the Calf Canyon (start on 19 April)/Hermits Peak (start on 6 April) fire start in the center of the animation; to the northeast of that fire, the Cooks Peak fire that started on 17 April is mostly contained as of 10 May; the Cerro Pelado fire (start on 19 April) to the west of Santa Fe is also apparent.

Suomi NPP Day Night Band imagery on 10 May 2022. Note the 3 faint smoke plumes emitted from the Calf Canyon and Hermits Peak fires. The moon had set by the time Suomi NPP overflew New Mexico.

Bolt out of the blue

May 10th, 2022 |

Florida is one of the lightning capitals of the world, so residents need to be constantly aware of lightning safety. NOAA/CIMSS LightningCast might be able to help with that.

A tree and home in Sebring, Florida were suddenly struck by lightning on the morning of Saturday, May 7th. A line of storms was edging its way eastward. A neighbor who was outside at the time said, “It wasn’t raining. It was nice and warm. It was cloudy, but that was it. And then boom!” This underscores how easy it is to be caught unaware of potential lightning danger.

LightningCast can help with users’ situational awareness. LightningCast is an experimental deep-learning model trained on thousands of GOES-R ABI and GLM images to predict the probability of next-hour lightning occurrence. In the animation below, the red dot is Sebring, Florida.

LightningCast probability contours, GOES-16 ABI imagery (grayscale background), and GOES-16 GLM flash-extent density (shaded color). The red dot is the approximate location of the “bolt out of the blue”.
Florida homeowner stunned by nearby lightning strike. Credit: FOX13 Tampa Bay

Below is a time series of LightningCast probability and GLM observations around the home in Sebring. Lightning struck the tree and home at 8:21 EDT, marked by the vertical black line below. You can see a rapid increase in probability of lightning from 11:26 to 11:36 UTC (7:26 to 7:36 EDT), reaching 70%. This was about 25 minutes before the first nearby lightning strike and 45 minutes before the Sebring home was struck.

The animation below from the National Weather Service lightning safety page shows that most lightning casualties occur before a thunderstorm is fully overhead, or before it fully departs the area, when people might not realize their vulnerability to lightning and don’t seek shelter soon enough or leave shelter too soon.

Animation depicting the threat of lightning casualties as a function of a hypothetical storm moving into the area.