Anak Krakatau Ash: Where Will the Wind Carry It?

TEMPO.CO, Jakarta - Volcanic ash has spread beyond the peak of Mount Anak Krakatau over the past two days. This was confirmed on Tuesday, September 8, 2026, at 04.00 WIB, based on information from Center for Volcanology and Geological Hazard Mitigation (PVMBG) and VAAC Darwin and analysis of RGB Himawari-9 images. The ash spread to an altitude of 6,000 feet in the lower atmosphere or at the surface, and it was observed moving towards the south-southwest or the Indian Ocean.

The Regional Meteorology, Climatology, and Geophysics Agency (BMKG) for Region II predicts low rainfall for the entire Banten region in September to October 2026 (0-100 mm/month). Medium to high rainfall is predicted to start in November and then increase until early 2027.

This rainfall prediction and the expected wind direction and strength serve as guidelines for the local provincial government when developing policies. "For example, on September 9, the wind is blowing towards the northwest, meaning that the educational process in the eastern areas such as Tangerang, Jakarta, and Bogor is safe," said the Head of the Regional Disaster Management Agency (BPBD) of Banten Province, Lutfi Mujahidin, to Tempo on Tuesday night, September 8, 2026.

Here are the wind conditions at Mount Anak Krakatau and its surrounding waters.

1. Monday, September 7, 2026

In general, the lower atmosphere is dominated by southeasterly winds of 5 to 25 knots. Meanwhile, winds in the middle atmosphere blow from the north-northeast to the southeast at speeds of 10-15 knots. In the upper atmosphere, winds blow from the north-northeast at speeds of 5-50 knots.

2. Tuesday, September 8, 2026

In the lower atmosphere, the wind is predominantly from the east-southeast, with speeds ranging from 5 to 20 knots. In the middle atmosphere, winds come from the northeast at speeds of 5-15 knots. In the upper atmosphere, winds blow from the northeast at speeds of 5-25 knots.

3. Wednesday, September 9, 2026

In the lower atmosphere, the wind is predominantly from the east-southeast, with speeds ranging from 5 to 20 knots. In the middle atmosphere, winds blow from the west-northwest at speeds of 5-10 knots. In the upper atmosphere, winds blow from the northeast to southeast at speeds of 5 to 45 knots.

4. Thursday, September 10, 2026

In the lower atmosphere, the wind is predominantly from the east-southwest, with speeds ranging from 2 to 20 knots. In the middle atmosphere, winds blow from the west-northwest at speeds of 5-10 knots. In the upper atmosphere, winds blow from the north-southeast at speeds of 15-50 knots.

5. Friday, September 11, 2026

In the lower atmosphere, the wind is predominantly from the northeast to east, with speeds ranging from 2 to 15 knots. In the middle atmosphere, winds blow from the northeast to the west at speeds of 5-10 knots. In the upper atmosphere, winds blow from the northeast at speeds of 25 to 50 knots.

6. Saturday, September 12, 2026

In the lower atmosphere, the wind is predominantly from the northeast to east, with speeds of 10 to 20 knots. In the middle atmosphere, winds blow from the northeast to southeast at speeds of 5-10 knots. In the upper atmosphere, winds blow from the northeast at speeds of 30-40 knots.

7. Sunday, September 13, 2026

In the lower atmosphere, the wind is predominantly from the east-southeast, with speeds ranging from 10 to 30 knots. In the middle atmosphere, winds blow from the northeast to southeast at speeds of 2-15 knots. In the upper atmosphere, winds blow from the northeast to east at speeds of 15 to 30 knots.

Read: Is Mount Anak Krakatau Still Erupting? Official Explains

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