Kilauea could begin erupting again within hours. The Hawaiian Volcano Observatory raised the volcano’s alert level from ADVISORY to WATCH on May 7 and, as of its May 13 status report, warned that Episode 47 of the summit eruption cycle that restarted in September 2023 could start “at any time now.” The aviation color code has shifted from YELLOW to ORANGE, putting Pacific air traffic on notice for possible ash emissions, and periodic spattering is already visible at the summit caldera’s north vent.
For communities on Hawai’i Island who have lived through 46 prior episodes, the rhythm is familiar but the pace this time is notable. Ground inflation has been climbing fast, and HVO scientists say the monitoring signals now match the patterns they have seen just before lava breaks the surface.
What HVO’s instruments are showing
Three streams of data drove the decision to elevate Kilauea to WATCH/ORANGE.
The most concrete is the Uekahuna tiltmeter, which measures ground deformation at the summit in real time. As of May 13, inflationary tilt had reached approximately 14.1 microradians since Episode 46 ended. That is a direct measurement, not a model estimate, and the shape of the inflation curve closely tracks the buildup HVO recorded before previous episodes. The pattern is now well established across this eruption cycle: steady pressurization, then a sharp deflation the moment lava reaches the surface.
Second, HVO cited changes in seismic wave velocities beneath the caldera. As magma rises and fractures open or close underground, the speed at which seismic waves travel shifts in characteristic ways. Observatory scientists compared the current signatures with recordings from earlier episodes and found them consistent with pre-eruption conditions. The raw waveform data have not been published, so outside researchers cannot independently replicate the analysis, but the technique itself is well established in volcano monitoring.
Third, and most visually striking, HVO staff observed intermittent spattering at the north vent on the evening of May 13, visible on the observatory’s public V1cam feed. Spattering means magma is already reaching near-surface fractures. Combined with strong inflation, it suggests that only a modest additional pressure increase may be needed to trigger sustained lava fountaining.
HVO’s initial Volcanic Activity Notice on May 7 flagged both the geophysical data and the spattering as the basis for the upgrade. By May 12, a daily update narrowed the forecast window to May 12 or 13, with May 14 considered less likely. The May 13 report tightened it further to “at any time now.”
What Episode 46 looked like on the ground
Episode 46, the most recent eruption before the current buildup, produced lava fountaining from the same north vent area within the summit caldera. HVO’s May 13 report referenced the end of Episode 46 as the baseline for measuring the current inflationary tilt of 14.1 microradians, but the observatory has not published a detailed summary of Episode 46’s exact duration or peak intensity in the notices available as of mid-May 2026. What is known from the broader pattern of the cycle that restarted in September 2023 is that most recent episodes have been relatively brief summit events, confined to the caldera floor and characterized by lava fountaining, elevated sulfur dioxide emissions, and intermittent vog impacts for downwind communities along the Kona coast. Residents in those areas have described a recurring routine during prior episodes: checking air quality reports each morning, keeping windows closed on high-vog days, and adjusting outdoor plans around the Hawai’i Department of Health’s advisories. The episodes have not forced evacuations, but they have made daily life measurably harder for people with asthma or other respiratory conditions when SO₂ output is high.
What WATCH and ORANGE actually mean
Under the USGS volcano alert system, WATCH does not mean an eruption has started. It means the volcano is showing heightened or escalating unrest and the potential for eruption has increased significantly. The paired ORANGE aviation code warns airlines and pilots that an eruption is possible and could produce significant ash.
Together, the two designations trigger a coordination chain. HVO shares its assessments with the National Weather Service, the Federal Aviation Administration, and local emergency managers, who then decide whether to reroute flights, close trails, or issue public advisories. It is the step just below WARNING/RED, which is reserved for eruptions already underway and posing significant hazards.
What is still unknown
Several gaps remain, even with the eruption looking imminent.
HVO has not yet published real-time sulfur dioxide emission rates from the May 13 spattering. SO₂ is the gas that produces vog, the volcanic smog that drifts downwind and can aggravate respiratory conditions, particularly along the Kona coast. Without measured flux data, it is impossible to say whether Episode 47 will be a relatively low-emission event or something more intense. HVO’s May 13 report noted that SO₂ emissions were expected to rise once fountaining began, but offered no specific projections.
The exact start time is also not locked in. Volcanic systems can stall. Magma may pond just below the surface without finding a stable pathway upward, or it could intrude laterally in ways that temporarily relieve pressure. HVO’s own language has consistently preserved the possibility of delay, even as the forecast window has tightened from a three-day range to something closer to hours.
Hawai’i Volcanoes National Park has not issued closure notices specific to Episode 47, though its general visitor guidance advises checking conditions before entering the summit area. The County of Hawaii Civil Defense Agency has standing protective-action guidance for tephra and vog from earlier episodes, but no Episode 47 advisory had appeared as of the most recent HVO update. Officials appear to be waiting for confirmation that lava has actually broken the surface before activating new alerts, a standard approach that can nonetheless leave visitors uncertain about access in the interim.
A broader scientific question looms in the background: whether the intervals between episodes are shortening, which could signal a change in Kilauea’s magma supply rate. The 14.1-microradian tilt buildup since Episode 46 is a useful benchmark, but HVO has not published a comparison table covering all prior inter-episode intervals. Without that data, it is difficult to say whether pressurization is accelerating or simply following the same rhythm at a slightly different tempo.
What residents and travelers should watch for next
The next major signal will be unambiguous: either lava fountains from the north vent and HVO escalates to WARNING/RED, or the inflation stalls and the observatory holds at WATCH while reassessing its timeline.
If fountaining begins, the immediate concerns shift to sulfur dioxide output and tephra fallout. Downwind communities, especially those on the western side of the island, will want to monitor air quality reports from the Hawai’i Department of Health. People with asthma or other respiratory conditions are typically advised to limit outdoor exposure when vog levels spike.
For visitors, the practical step right now is straightforward: check HVO’s daily updates and the national park’s conditions page before heading to the summit. Access can change within minutes once an eruption starts, and cell service in parts of the park is unreliable. Having a plan before arriving matters more than reacting on the fly.
How Episode 47’s opening hours will shape what comes next
Kilauea has been cycling through these episodes since the summit eruption cycle restarted in September 2023, and the communities around it have developed a practiced awareness of what each alert level means for daily life. But each episode is its own event, with its own intensity and duration. Episode 47 has not started yet. When it does, the data will tell the story quickly.
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*This article was researched with the help of AI, with human editors creating the final content.
