Both vents inside Kilauea’s Halema’uma’u crater are glowing again. Overnight webcam feeds show incandescence returning to the north and south openings on the crater floor, and tiltmeters at the summit are ticking upward hour by hour as fresh magma pushes into the shallow reservoir beneath the caldera. On the strength of that signal, the USGS Hawaiian Volcano Observatory on May 28 opened its Episode 48 forecast window, placing the next fountain eruption somewhere between today, Wednesday, May 28, and Saturday, May 30, 2026.
The last eruption, Episode 47, ended just two weeks ago. It began on May 14 at 3:27 p.m. HST and shut down by 12:27 a.m. on May 15, a roughly nine-hour burst that sent lava approximately 650 feet into the air. Peak effusion rates hit 360 to 390 cubic yards per second, with an average of 270 cubic yards per second across the episode. Since that eruption drained pressure from the summit, the volcano has been quietly rebuilding.
How HVO forecasts the next fountain
The observatory’s prediction method centers on tilt measurements recorded at the Uekahuna station near the summit. As magma refills the shallow reservoir, the ground surface inflates in a pattern that tiltmeters can track in near-real time. HVO scientists have described in their Volcano Watch series how they derive a “target tilt” value from the behavior of previous episodes. When the instrument readings approach that threshold, the probability of a new eruption climbs sharply, and the forecast window tightens.
That method has proven broadly reliable across dozens of episodes in the current sequence, but it is not a clock. Earlier this month, according to a notice on the observatory’s volcano messages page, a sharp and unexplained deflation event registered what HVO described as roughly 1 microradian of drop on the Uekahuna tiltmeter shortly after 4 p.m. HST. No seismic swarm preceded it, and no lava reached the surface. The pressure loss was enough to push the Episode 48 forecast back to May 26 through 27 at the time. When inflation resumed, the observatory revised the window forward to its current May 28 through 30 range.
No specific tilt values for the ongoing recovery have been published in the observatory’s primary updates, so the exact rate of reinflation and how close the chamber sits to its target threshold cannot be independently confirmed from public data as of this writing. Kilauea remains at ADVISORY/YELLOW, the alert level HVO has maintained between fountain episodes throughout the current eruptive phase. The observatory has not signaled any imminent upgrade to WATCH/ORANGE, though its own protocols allow rapid escalation once precursory tremor or accelerating tilt appears.
Why Episode 48 could look very different from Episode 47
One of the defining features of Kilauea’s current eruptive sequence is its variability. Episode 47’s 650-foot fountains were relatively modest. Earlier this year, according to HVO reports and ash advisories issued at the time, Episode 43 produced fountains reaching roughly 1,300 feet, and NOAA’s Washington Volcanic Ash Advisory Center tracked a plume that exceeded 22,000 feet above sea level. That eruption prompted the USGS to issue a full Volcano Warning and led the National Park Service to temporarily close the Kilauea summit area and a stretch of Highway 11 because of tephra fallout.
There is no reliable way to predict in advance whether Episode 48 will resemble the smaller Episode 47 or the far more disruptive Episode 43. The volume of magma stored, the geometry of the conduit, and the gas content of the melt all influence fountain height and eruption duration, and those variables are not fully observable before lava breaks the surface.
The Smithsonian Institution’s Global Volcanism Program published a volcanic activity summary for Kilauea on May 13, offering an independent institutional overview of the ongoing sequence. That report predates the latest forecast revision and does not reflect the newest tilt behavior or the updated Episode 48 timing, but it provides useful background on the eruption’s broader trajectory.
Park access, webcams, and air quality right now
As of the May 28 update, Hawaii Volcanoes National Park remains open, though the National Park Service has restricted access to certain summit overlooks during prior episodes and can close areas on short notice when conditions change. Visitors should check the park’s current conditions page before heading to the summit for the latest on road and trail closures.
HVO maintains several live webcams pointed at Halema’uma’u crater, including thermal and visible-light views that update every few minutes. These feeds are the easiest way for the public to watch for the onset of fountaining in real time. For air quality, the Hawaii Department of Health posts vog forecasts and sulfur dioxide advisories through its air quality monitoring network, which is especially useful for residents and visitors with respiratory sensitivities.
For communities on Hawaiʻi Island, particularly those downwind of the summit under prevailing trade-wind conditions, the recurring hazards are familiar: elevated sulfur dioxide emissions that worsen vog, fine ash and Pele’s hair that can irritate lungs and eyes, and occasional lava spatter or ballistic blocks near the vents. These risks intensify during active fountaining and taper off between episodes, but gas emissions can remain elevated even during pauses.
The current ADVISORY/YELLOW status reflects that hazards are confined to the summit area. There is no indication of magma migrating toward the East Rift Zone or Southwest Rift Zone, and no sign of the kind of directed intrusion that would threaten lower-elevation communities. Any shift in that picture, such as seismic swarms migrating away from Halema’uma’u or deformation patterns suggesting lateral movement, would trigger revised alerts and civil defense messaging from Hawaiʻi County.
Why the forecast window is a probability range, not a countdown
A window like May 28 through 30 is best understood as a period of elevated likelihood. If the magma reservoir falls short of its target tilt, or if another unexplained deflation bleeds off pressure the way one did earlier this month, the next eruption could arrive later than expected or differ markedly in character from anything the current sequence has produced so far.
What the instruments do confirm is that Kilauea’s summit is actively recharging. Glow has returned to both vents. Tilt is climbing. And the observatory, which has tracked this eruptive sequence through 47 prior episodes, considers the next one close enough to put a three-day window on the calendar. Whether fountains break out tonight or slip past Saturday, the monitoring network is watching every microradian of change beneath Halema’uma’u.
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*This article was researched with the help of AI, with human editors creating the final content.
