By Rishav Kothari
Friday, September 4, 2026 21:24 UTC
A high-level eruption at Anak Krakatau, #Indonesia, ejected #volcanic ash up to 15 km (50 000 feet) above sea level at 00:50 WIB on September 5, 2026 (17:50 UTC on September 4).
Darwin #Volcanic #AshAdvisory Center (VAAC) later tracked the ash moving west at approximately 74 km/h (46 mph), while a second layer to about 5.5 km (18 000 feet) extended south.
SIGMETs were issued for the #Jakarta and #Melbourne flight #information regions.
Darwin VAAC recorded a rapid increase in reported ash #altitude late on September 4.
Advisory 2026/163 placed ash at FL070, equivalent to approximately 2 km (7 000 feet) above sea level (a.s.l), at 23:00 WIB (16:00 UTC).
Advisory 2026/164 identified a high-level eruption to approximately 14 km (45 000 feet) a.s.l., at 23:30 WIB (16:30 UTC).
Ten minutes later, Advisory 2026/165 noted ash at approximately 15 km (48 000 feet), moving west at about 93 km/h (58 mph).
Darwin VAAC said the high-level emission was continuing and based the altitude estimate on an infrared cloud-top temperature of −68°C (−90.4°F).
Ash movement and subsequent forecasts were based on Himawari-9 satellite imagery and consensus model #guidance.
Advisory 2026/167, issued at 19:10 UTC, identified two ash layers in satellite imagery at 01:50 WIB on September 5 (18:50 UTC on September 4).
Ash extending from the surface to 15 km (48 000 feet) was moving west at approximately 74 km/h (46 mph), while a second layer extending to about 5.5 km (18 000 feet), was moving south at approximately 19 km/h (12 mph).
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