This website works best with a newer web browser such as Chrome, Firefox, Safari or Microsoft Edge. Internet Explorer is not supported by this website.

CIMSS Satellite Blog

MENU

Fast-moving wildfires produce pyrocumulonimbus clouds over South Korea

By Scott Bachmeier •

2.5 minute JMA Himawari-9 “Red” Visible (0.64 µm, top), Shortwave Infrared (3.9 µm, center) and “Clean” Infrared Window (10.4 µm, bottom) images, from 0200-1047 UTC on 25 March [click to play animated GIF | MP4]

2.5-minute JMA Himawari-9 “Red” Visible (0.64 µm), Shortwave Infrared (3.9 µm) and “Clean” Infrared Window (10.4 µm) images (above) showed the formation of 3 pyrocumulonimbus (pyroCb) clouds that were spawned by a wildfire complex in the eastern part of South Korea on 25 March 2025. The pyroCbs exhibited cloud-top 10.4 µm infrared brightness temperatures (IRBTs) in the -40s C (denoted by shades of blue to cyan), a necessary condition to be classified as a pyroCb. The first 2 small, brief pyroCb pulses formed at 0832 UTC and 0840 UTC, with the largest and more long-lived pyroCb developing at 0842 UTC. These were the first pyroCb clouds to be documented in South Korea.

2.5-minute JMA Himawari-9 Shortwave Infrared (3.9 µm) images, from 0300-1402 UTC on 25 March [click to play animated GIF | MP4]

2.5-minute Himawari-9 Shortwave Infrared images (above) showed that the wind-driven wildfire complex made a rapid eastward run beginning around 0700 UTC, reaching the coast shortly after 1200 UTC. These fires burned more than 111000 acres, making it South Korea’s largest wildfire event on record. At least 28 fatalities have been reported.

A toggle between surface analyses at 0000 UTC and 1200 UTC (below) indicated that a low pressure system had moved from northeastern China to the Yellow Sea — and tightly spaced isobars behind the low across the Korean Peninsula at 1200 UTC supported the presence of strong winds that were responsible for the rapid eastward run of the wildfire complex that produced the pyroCb clouds. As the cold front associated with this low pressure passed Cheongju Air Base (RKTU, located west-northwest of the fires) there was a wind gust to 43 kts (49 mph) at 0606 UTC — while at Daegu (RKTN, located south of the fires) there was a wind gust to 30 kts (35 mph) at 0900 UTC.

Surface analyses at 0000 UTC and 1200 UTC on 25 March

10-minute Himawari-9 True Color RGB images created using Geo2Grid (below) also revealed the hazy signature of Asian blowing dust that was streaming eastward across the Korean Peninsula — including a SW-to-NE oriented band of dense airborne dust focused along the aforementioned cold front (0700 UTC image). The pyroCb cloud was just crossing the coast of Korea at 0900 UTC.

10-minute JMA Himawari-9 True Color RGB images, from 0000-0910 UTC on 25 March [click to play animated GIF | MP4]

Categories: Fire detection, Geo2Grid, Himawari-9, Red-Green-Blue (RGB) images