The floor of Halemaʻumaʻu crater is still glowing. Both vents at Kilauea’s summit remain lit from below, a sign that molten rock lingers just beneath the surface even as the volcano sits in a temporary pause. But that pause is ending. The Hawaiian Volcano Observatory, the USGS division responsible for monitoring Hawaii’s volcanoes, is forecasting the next lava fountaining episode between Sunday, May 25, and Wednesday, May 28, as fresh magma steadily reinflates the summit.
The eruption series at Kilauea has now produced 47 separate fountaining episodes since it began, each one a burst of towering lava jets followed by days or weeks of quiet recharging. Episode 48 appears to be next in line, and for residents downwind of the summit and visitors headed to Hawaii Volcanoes National Park this holiday weekend, the timing matters.
What Episode 47 looked like
The most recent burst of activity offers the clearest preview of what may come. Episode 47 began at 3:27 p.m. HST on May 14 and ran until 12:27 a.m. on May 15, a roughly nine-hour event that sent lava fountains approximately 650 feet (200 meters) into the air. The volcanic plume climbed to about 20,000 feet above sea level, high enough to trigger aviation alerts across the region, according to HVO’s message logs.
At its peak, lava poured onto the crater floor at a rate of 360 to 390 cubic yards per second. Ash and fine strands of volcanic glass called Pele’s hair drifted onto communities downwind. Once the fountains stopped, HVO dropped Kilauea’s alert level from WATCH to ADVISORY and shifted the aviation color code from ORANGE to YELLOW, signaling that the volcano was no longer actively erupting but remained in a heightened state.
Now the cycle is repeating. The Uēkahuna tiltmeter on the caldera rim is tracking the slow upward tilt of the summit surface, the signature of a magma reservoir refilling beneath the crater. That deformation pattern has preceded every recent fountaining episode and forms the backbone of HVO’s forecast models.
How HVO builds its forecast windows
The observatory’s approach, detailed in a technical essay published earlier in this eruption series, works like a pressure gauge. Each fountaining episode drains a portion of the shallow magma reservoir. As that reservoir refills, the summit reinflates until the pressure exceeds the strength of the rock sealing the vent. The volume of lava erupted in the previous episode serves as a rough proxy for how much magma must flow back in before the next event triggers.
Over dozens of episodes, this method has allowed HVO to narrow forecast windows to spans of just a few days. The exact start time still carries uncertainty measured in hours, but the broad timing has proven reliable enough that park managers and emergency responders now use it to plan closures and staffing in advance.
What remains uncertain about Episode 48
HVO has confirmed that inflation is “underway” but has not released specific tilt values or inflation rates from the Uēkahuna station. Without those numbers, it is not possible to independently gauge whether the recharge is running ahead of or behind the pace that preceded Episode 47.
Projections for maximum fountain height, plume altitude, and effusion rate have also not been issued. Each episode in this series has varied in intensity. Episode 47’s 650-foot fountains and 20,000-foot plume were significant, but earlier episodes have been both larger and smaller. The outcome depends on how much magma accumulates before the vent seal breaks, and that volume will not be known until the eruption begins.
Tephra fallout is equally unpredictable until wind conditions at eruption time become clear. During Episode 43 earlier in 2026, hazardous ashfall forced the National Park Service to close the summit area and shut down a stretch of Highway 11 between mile markers 24 and 40. Similar closures could happen again, but the geographic footprint of any ashfall depends on wind speed and direction, variables that weather models can only approximate a few days out.
What residents and visitors should prepare for
For anyone living downwind of the summit or planning a trip to the park this weekend, the practical first step is to start checking HVO’s daily updates and the park service’s alert pages by Saturday. If Episode 48 triggers within the forecast window, changes will come fast: alert levels will jump from ADVISORY back to WATCH or higher, the aviation color code will shift to ORANGE or RED, and park access near the summit will likely be restricted. Highway 11 closures between mile markers 24 and 40 are a real possibility based on the Episode 43 precedent.
Communities that caught ash and Pele’s hair during previous episodes should take familiar precautions: bring pets indoors during active fountaining, cover rainwater catchment systems, and avoid driving in low-visibility ash conditions. Residents with respiratory issues should keep masks or respirators accessible in case vog and fine ash concentrations spike.
Inside the park, visitors should expect shifting closures, crowded viewpoints, and limited parking if lava becomes visible from public overlooks. Rangers may move barriers and reroute traffic with little warning to keep people clear of hazardous areas, particularly downwind of the vent where tephra, gas, and sudden wind shifts can create localized dangers. Anyone planning sunrise or nighttime viewing should bring flashlights, warm layers, and enough fuel and water to handle delays if traffic backs up during peak hours.
Why Kilauea’s fountaining cycle shows no sign of stopping
Forty-seven episodes in, the pattern at Kilauea’s summit shows no sign of winding down. The shallow magma system continues to recharge after each pause, and every quiet interval so far has been followed by another round of fountaining at Halemaʻumaʻu. That does not guarantee Episode 48 will mirror its predecessors in scale or duration, but it strongly suggests that short, intense fountain bursts separated by days of reinflation remain the most likely near-term behavior.
For volcanologists, the repeating cycle has turned Kilauea into a rare natural laboratory for testing short-term eruption forecasts. Each new episode adds another data point linking erupted volume, tilt trends, gas output, and seismicity. Over time, that growing dataset could refine the models enough to narrow forecast windows even further or to flag subtle precursors that distinguish larger episodes from smaller ones.
For everyone else, the takeaway is simpler: as long as the summit keeps reinflating after each pause, the next round of lava fountains is a matter of when, not if. HVO’s daily updates remain the most reliable way to track that timeline, and this weekend, they are worth watching closely.
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*This article was researched with the help of AI, with human editors creating the final content.
