Kilauea’s next lava-fountaining episode could erupt within days, USGS scientists say

Scientists at the U.S. Geological Survey say Kilauea’s summit is again primed for one of its short, violent bursts of lava fountaining, with the next episode likely to begin during the final week of August 2026. The Hawaiian volcano has been erupting in a distinctive stop-and-start pattern since late 2024, staging dozens of separate fountaining episodes at its summit crater rather than a single continuous flow. Each episode arrives after a pause of days to weeks, and monitoring teams have grown skilled at reading the buildup well enough to give the public a forecast window.

The forecast window from the Hawaiian Volcano Observatory

Analysts at the observatory that watches the volcano have narrowed the expected onset of the next episode to a span of several days rather than a single date, reflecting the inherent uncertainty in predicting when the underground system will reach its tipping point. The agency’s running Kilauea volcano updates track summit inflation, earthquake counts and gas output to time each cycle. The most recent fountaining episode ended in mid-August after several hours of activity, and the summit immediately began reinflating as fresh magma refilled the shallow reservoir. That steady swelling of the ground surface is the clearest sign that pressure is rebuilding toward another release.

How episodic fountaining works

Kilauea’s current behavior differs sharply from the long-lived lava-lake activity and the destructive 2018 lower-East-Rift-Zone eruption that many residents remember. In the ongoing sequence, lava erupts from vents inside Halemaumau crater at the summit, jets skyward for a matter of hours, then stops as the pressure that drove it is spent. Fountains during recent episodes have reached hundreds of feet in height before subsiding. Between episodes, the conduit largely drains and the surface deflates, only to inflate again as magma resupply resumes. This rhythm of rapid inflation followed by an abrupt eruptive release has repeated dozens of times, giving forecasters an unusually reliable template for anticipating the next event. In the hours before an episode begins, instruments typically register a sharp increase in ground tilt and a rise in volcanic tremor as magma pushes toward the surface, precursors that let scientists narrow the timing from a multi-day window to a matter of hours once the final buildup is underway. Those short-term signals, layered on top of the longer inflation trend, are what allow the observatory to distinguish an ordinary pause from the immediate lead-up to fountaining.

What the alert level signals

The volcano’s status is communicated through a standardized system that pairs a color code with an alert level, a framework the USGS uses at every monitored American volcano. Under the agency’s volcanic alert-level definitions, a designation of “watch” indicates that a volcano is exhibiting heightened or escalating unrest with the potential for eruption, or that an eruption is underway but poses limited hazards. Because the summit activity is confined within the caldera and the closed area of Hawaii Volcanoes National Park, the danger to populated areas has so far remained low, even as the eruptions produce dramatic fountaining. The alert level is adjusted as conditions change, dropping when an episode ends and the summit quiets.

The hazards that persist between episodes

Even a summit eruption that threatens no homes carries health and safety risks that spread far beyond the crater rim. The most persistent is volcanic smog, a haze known as vog that forms when sulfur dioxide and other volcanic gases react in the atmosphere. The National Park Service and health agencies warn that vog can aggravate asthma and other respiratory conditions across the island and, depending on wind, well beyond it. Fountaining episodes also loft fine volcanic glass fibers called Pele’s hair, which winds can carry downwind and which can irritate skin and eyes. Ashfall and abrupt shifts in gas emissions are additional concerns that prompt the observatory to caution visitors and downwind communities each time an episode begins. Detailed hazard information is maintained alongside the observatory’s monitoring on its Hawaiian Volcano Observatory pages.

Why the monitoring matters

The value of the current forecasting is that it converts a spectacular but hazardous natural process into something the public can plan around. Emergency managers, park officials and air-quality monitors use each projected window to prepare for gas emissions, manage viewing areas and warn sensitive populations before fountaining resumes. The broader scientific payoff is a rare, closely observed record of how a basaltic volcano cycles through repeated eruptions, data that sharpens forecasting not only at Kilauea but at similar volcanoes worldwide. For residents of Hawaii Island, the practical takeaway is straightforward: another burst of lava is expected imminently, it will most likely stay within the summit area, and the main precaution is to heed air-quality guidance when volcanic gas drifts across inhabited districts. The observatory continues to update its outlook as instruments register the final stages of pressurization, and any shift in the timing or character of the eruption is reflected in its regular notices.

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

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