El Niño linked to Indonesian wildfires and Super Typhoon Choi-Wan activity
The National Weather Service has issued extreme heat warnings for parts of Southern California, including Los Angeles, through Thursday, with temperatures expected to reach the high 30s Celsius this week. Burbank, a suburb north of Los Angeles, recorded 39C on Saturday, falling a few degrees short of the October record for the region set in 1987.
A persistent area of high pressure will remain in place this week, the service said, leading to further hazardous hot weather and increased fire risk across the region. The heat marks an unusual October event for Southern California, and the service said the conditions will keep fire danger elevated through the week.
The California advisory comes as the broader Pacific region faces compounding extreme-weather conditions. In Indonesia, an extreme wildfire season has peaked over the past month, with Western Kalimantan on Borneo and southern Sumatra particularly affected. The lack of rainfall has dried the usually waterlogged tropical soils, allowing fires to spread quickly above and below the surface.
Indonesia’s soils are rich in peat, and the smoke produced by the fires contains higher levels of toxic gases including sulphur dioxide and carbon monoxide. Cities in surrounding areas and as far as Malaysia and Singapore have experienced reduced air quality in recent weeks as a result. Drought and wildfires are more common in this part of the world during El Niño events owing to suppressed thunderstorm activity.
El Niño is also contributing to an extremely active period for tropical cyclones in the Pacific Ocean. After recent hurricanes in the eastern half of the basin, Super Typhoon Choi-Wan developed on 30 September and moved through the Northern Mariana Islands as a tropical storm. The storm caused power outages on the island of Tinian and forced the closure of schools and government offices before clearing the islands on Sunday.
Choi-Wan then underwent rapid intensification, reaching sustained winds of 150mph and gusts of up to 180mph by Sunday night. As of the latest reports, the system was a Category 4 typhoon on a strengthening trend southeast of Japan. The storm is expected to curve away from mainland Japan and areas affected by Typhoon Dujuan last month while steadily weakening over the coming week.