Semeru volcano (East Java, Indonesia): pyroclastic flow today

Pyroclastic flow from Semeru this morning (image: Pusat Vulkanologi dan Mitigasi Bencana Geologi)

A strong eruption occurred at the volcano this morning.

At about 09:30 AM local time, a pyroclastic flow descended over the southern slope. The block-and-ash flow has been likely triggered by the gravitational collapse of the lava dome in the inner summit crater as well as the lava flow on the steep slope of the volcano. It also formed secondary ash columns (so-called phoenix clouds), as can be seen in the image, and rose about 700 meters above the summit.

Pyroclastic flows are deadly, turbulent hot avalanche of lava rock fragments of all sizes embedded in a mixture of turbulent gas and ash racing down slopes.

Beyond the 8-km zone, people should also stay at least 500 meters away from the riverbanks along Besuk Kobokan, as this area remains at risk from potential expansion of pyroclastic density currents and lava flows, which may travel up to 13 km from the summit.

Reventador Volcanic Ash Advisory: ash plume to 15,000 ft (4,600 m) as of Nov 4, 20:10 UTC

Mild explosive activity continues intermittently. The Volcanic Ash Advisory Center (VAAC) Washington reported sporadic emissions of volcanic ash.
Original VAAC bulletin:

FVXX21 at 20:47 UTC, 04/11/26 from KNES
VA ADVISORY
DTG: 20261104/2045Z

VAAC: WASHINGTON

VOLCANO: REVENTADOR 352010
PSN: S0004 W07739

AREA: ECUADOR

SOURCE ELEV: 11686 FT AMSL

ADVISORY NR: 2026/1167

INFO SOURCE: GOES-19. VONA. WEBCAM. NWP MODELS.

ERUPTION DETAILS: INTMT VA EMS

OBS VA DTG: 04/2010Z

OBS VA CLD: SFC/FL150 N0001 W07746 - S0004 W07739
- S0005 W07740 - S0000 W07747 - N0001 W07746 MOV
NW 10KT

FCST VA CLD +6HR: 05/0200Z SFC/FL150 S0001 W07747
- S0004 W07739 - S0005 W07740 - S0002 W07748 -
S0001 W07747

FCST VA CLD +12HR: 05/0800Z SFC/FL150 S0004
W07748 - S0004 W07739 - S0005 W07739 - S0006
W07748 - S0004 W07748

FCST VA CLD +18HR: 05/1400Z SFC/FL150 S0004
W07748 - S0004 W07740 - S0005 W07739 - S0006
W07748 - S0004 W07748

RMK: VONA RCVD FR VA EMS. VA EMS OBS IN WEBCAM
AND STLT IMG EXT APRX 10NM NW FM SUMMIT. MVMT TO
SHIFT W BY T+12. FCST BASED ON VONA, STLT AND MDL
WINDS. ...GATLING

NXT ADVISORY: WILL BE ISSUED BY 20261105/0245Z

Fuego Volcanic Ash Advisory: ash plume to 15,000 ft (4,600 m) as of Nov 4, 18:00 UTC

Explosive activity continues. The Volcanic Ash Advisory Center (VAAC) Washington warned of a volcanic ash plume rising to an estimated 15000 ft (4600 m), or flight level 150.
Original VAAC bulletin:

FVXX22 at 18:29 UTC, 04/11/26 from KNES
VA ADVISORY
DTG: 20261104/1826Z

VAAC: WASHINGTON

VOLCANO: FUEGO 342090
PSN: N1428 W09052

AREA: GUATEMALA

SOURCE ELEV: 12346 FT AMSL

ADVISORY NR: 2026/1281

INFO SOURCE: GOES-19. WEBCAM. NWP MODELS.

ERUPTION DETAILS: FREQUENT VA EMS

OBS VA DTG: 04/1800Z

OBS VA CLD: SFC/FL150 N1428 W09052 - N1428 W09053
- N1426 W09105 - N1428 W09105 - N1428 W09052 MOV
W 10KT

FCST VA CLD +6HR: 05/0000Z SFC/FL150 N1428 W09052
- N1428 W09052 - N1421 W09102 - N1423 W09104 -
N1428 W09052

FCST VA CLD +12HR: 05/0600Z SFC/FL150 N1431
W09104 - N1428 W09052 - N1428 W09052 - N1429
W09105 - N1431 W09104

FCST VA CLD +18HR: 05/1200Z SFC/FL150 N1430
W09105 - N1428 W09053 - N1428 W09052 - N1428
W09105 - N1430 W09105

RMK: VA EMS OBS IN WEBCAM AND STLT IMG EXT APRX
15NM W FM SUMMIT. SW MVMT EXP BY T+6. FCST BASED
ON STLT AND MDL WINDS. ...GATLING

NXT ADVISORY: WILL BE ISSUED BY 20261105/0030Z

Lewotolo Volcanic Ash Advisory: ash plume to 7,000 ft (2,100 m) as of Nov 4, 16:19 UTC

Satellite image of Lewotolo volcano on 4 Nov 2026

Explosive activity continues. The Volcanic Ash Advisory Center (VAAC) Darwin warned of a volcanic ash plume rising to an estimated 7000 ft (2100 m), or flight level 070.
Original VAAC bulletin:

FVAU01 at 16:19 UTC, 04/11/26 from ADRM
VA ADVISORY
DTG: 20261104/1620Z
VAAC: DARWIN
VOLCANO: LEWOTOLOK 264230
PSN: S0816 E12330
AREA: INDONESIA
SOURCE ELEV: 1423M AMSL
ADVISORY NR: 2026/333
INFO SOURCE: HIMAWARI-9 CVGHM
ERUPTION DETAILS: VA TO FL070 REPORTED AT 04/1515Z MOV W
EST VA DTG: 04/1600Z
EST VA CLD: SFC/FL070 S0819 E12333 - S0825 E12239 - S0746
E12250 - S0811 E12335 MOV W 10KT
FCST VA CLD +6 HR: 04/2200Z NO VA EXP
FCST VA CLD +12 HR: 05/0400Z NO VA EXP
FCST VA CLD +18 HR: 05/1000Z NO VA EXP
RMK: CVGHM REPORTED ERUPTION TO 500M ABV THE SUMMIT. VA NOT
IDENTIFIABLE ON SAT IMAGERY DUE TO DARKNESS. VA IS EXPECTED
TO DISSIPATE WITHIN 3-6HRS. HEIGHT AND MOVEMENT BASED ON
MODEL GUIDANCE AND GROUND REPORT.
NXT ADVISORY: NO LATER THAN 20261104/2220Z=

Reventador Volcanic Ash Advisory: ash plume observed as of 04 Nov 2026, 08:30 UTC

Volcanic ash was seen in webcam images from Reventador as of 08:30 UTC on 4 November 2026. Forecasts indicate possible continued ash presence up to 18 hours after the observation.
Original VAAC bulletin:

FVXX21 at 08:59 UTC, 04/11/26 from KNES
VA ADVISORY
DTG: 20261104/0857Z

VAAC: WASHINGTON

VOLCANO: REVENTADOR 352010
PSN: S0004 W07739

AREA: ECUADOR

SOURCE ELEV: 11686 FT AMSL

ADVISORY NR: 2026/1164

INFO SOURCE: GOES-19. WEBCAM. NWP MODELS.

ERUPTION DETAILS: VA SEEN IN WEBCAM

EST VA DTG: 04/0830Z

EST VA CLD: SFC/FL150 N0001 W07748 - S0004 W07739
- S0005 W07740 - S0003 W07750 - N0001 W07748 MOV
NW 5KT

FCST VA CLD +6HR: 04/1430Z SFC/FL150 N0005 W07757
- S0004 W07739 - S0005 W07739 - S0002 W07800 -
N0005 W07757

FCST VA CLD +12HR: 04/2030Z SFC/FL150 N0002
W07756 - S0004 W07739 - S0005 W07740 - S0004
W07758 - N0002 W07756

FCST VA CLD +18HR: 05/0230Z SFC/FL150 N0003
W07755 - S0004 W07739 - S0005 W07739 - S0004
W07758 - N0003 W07755

RMK: OCNL VA EMS SEEN IN WEBCAM BUT WX CLDS OBSC
STLT IMAGERY. VA FCST THRU T+18 HRS BASED ON NWP
MDL GUIDANCE. ...COVERDALE

NXT ADVISORY: WILL BE ISSUED BY 20261104/1500Z