Kilauea’s latest fountains reached 660 feet and sent a plume 18,000 feet high

Lava fountains inside Kilauea’s Halemaumau crater climbed to about 660 feet (200 meters) on Nov. 5, and the plume above them reached roughly 18,000 feet above sea level. The 56th fountaining episode of the summit eruption began near 12:10 p.m. Hawaii time and stopped abruptly at 6:01 p.m., a run of just under six hours. Both figures come from the U.S. Geological Survey’s Hawaiian Volcano Observatory.

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The alert posture has already eased. An end-of-episode notice on the evening of Nov. 5 kept the volcano at WATCH with an aviation color code of ORANGE, while the observatory’s Saturday morning update on Nov. 7 listed ADVISORY and YELLOW as the summit began refilling.

Fountain height and the 18,000-foot plume

The observatory’s own update, posted at 8:24 a.m. Hawaii time on Nov. 7, states that fountains reached about 660 feet and that only the north vent produced fountaining during episode 56. A write-up by The Watchers, which relayed the observatory’s end-of-episode statements, adds a second reference point: by 4:43 p.m. the jets had already fallen to about 330 feet, so the peak was a mid-afternoon event and the last hour was a steady decline that ended with a sudden shutoff rather than a taper.

The plume figure rests on weather radar. The observatory put the top of the ash and gas column at 5,500 meters, or 18,000 feet, above sea level, citing National Weather Service radar returns, and the Honolulu forecast office and the Washington Volcanic Ash Advisory Center relayed the same altitude to aviation users. Upper-level winds pushed the plume toward Mauna Loa, while surface winds steered the falling tephra the other way, into the closed section of Hawaii Volcanoes National Park. Light tephra still reached Footprints and Pahala, and the observatory later noted trace amounts along Highway 11.

Laid out on the clock, the episode was brief and front-loaded in energy. Fountaining started at 12:10 p.m. Hawaii time, which is 22:10 UTC on Nov. 5. Effusion peaked about two hours later, the jets had roughly halved by late afternoon, and the activity cut off at 6:01 p.m. (04:01 UTC on Nov. 6). The observatory called that final stop abrupt, and an end-of-episode notice went out at 6:21 p.m., twenty minutes after the vents went quiet, restating the WATCH level and ORANGE color code.

For residents of the Big Island, the practical effect of an event like this one is the fallout downwind rather than the fountains, which stay far from communities. Tephra, the glassy fragments thrown up by the jets, is the material that landed in Pahala and at Footprints, and it is the reason the observatory tracks wind direction at both the surface and the plume altitude.

Eight million cubic yards in six hours

Tiltmeter data let the observatory convert a spectacle into a volume. About 6 million cubic meters of lava, or 8 million cubic yards, erupted during episode 56, an average of roughly 200 cubic meters per second. The peak was far higher, near 530 cubic meters per second around 2 p.m., timing that fits the tallest fountains. The Uekahuna tiltmeter at the summit recorded about 17 microradians of deflationary tilt as the magma chamber drained, a signature that reverses once the system recharges.

All of the lava stayed within Halemaumau. The Watchers account notes that the vents and flows never left the crater floor, so the hazard in this episode was airborne rather than effusive: falling tephra, volcanic gas and the aviation risk posed by the column. Hawaii Volcanoes National Park keeps the downwind area closed during these events, and the park’s alerts page is where visitors check for current access.

Inflation began immediately after the fountaining shut off. By the Saturday morning update the tiltmeter had recovered about 5.1 microradians, roughly 30 percent of the 17 microradians lost, which is the measurement the observatory uses to judge how soon the next episode could arrive.

Reinflation and the outlook for episode 57

The observatory’s forecast language is plain: the next fountaining episode is “likely several weeks away.” An aviation notice issued as episode 56 ended went further, calling summit fountaining unlikely for the next several weeks. The observatory has said most fountaining episodes in this sequence lasted one day or less.

The current sequence has run in on-and-off fashion since late December 2024, according to the USGS Kilauea page, and most episodes since then have been short. Episode 56 at nearly six hours sits at the long end of that range, and the roughly 8 million cubic yards it erupted is a large single draw on the summit reservoir.

The observatory has also kept the same format for each update, which makes comparisons across episodes straightforward: the height of the fountains, the plume altitude from radar, the erupted volume from tilt, and the tephra footprint. Episode 56’s four measurements, 660 feet, 18,000 feet, 8 million cubic yards and nearly six hours, give later episodes a clear yardstick.

What remains unsettled is the timing, which the observatory frames only as several weeks. The measurement to watch is the cumulative tilt at Uekahuna against the roughly 17 microradians released on Nov. 5; the daily HVO updates carry that number, and the 5.1 microradians recovered by Nov. 7 is the starting point for any estimate of when episode 57 could begin.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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