Kīlauea’s Irregular Recharge Delays Episode 55 Amidst Precursory Overflow

Key points

• Precursory low-level lava activity began at 12:45 p.m. HST on September 7, 2026, from the north vent in Halemaʻumaʻu crater.
• The USGS Hawaiian Volcano Observatory (HVO) raised the alert level from ADVISORY to WATCH and the aviation color code from YELLOW to ORANGE in response to the overflow.
• Ten overflows occurred between September 7 and 8, creating two lava flow lobes that extended approximately 0.5 miles from the north vent before activity paused overnight.
• Summit inflation has been irregular since Episode 54 ended on August 25, with tiltmeters showing three distinct interruptions in the recharge process, unlike previous predictable cycles.
• HVO forecasts Episode 55 to begin between September 7 and 10, but a secondary window of September 10–13 exists if significant deflation occurs before fountaining starts.
• All three vents (north, south, and west) showed glow overnight on September 6–7, but only the north vent produced overflow; the south vent’s glow was the first since Episode 54 ended.

Background

This activity is part of a continuous eruption cycle at Kīlauea that began in December 2024. As of September 2026, the volcano has completed 54 high-fountaining episodes, surpassing the historical record of 47 episodes set by Puʻuʻōʻō in the 1980s. Previous episodes, such as Episode 54 on August 25, typically lasted less than 12 hours and produced fountains reaching up to 500 feet. The current irregularity in recharge marks the first time in this cycle that the predictable deflation-inflation pattern has been disrupted by internal magma system changes rather than external factors like Hurricane Lala in August.

How outlets are covering it

Big Island Video News and Maui Now both report the immediate precursory activity and the subsequent pause in overflow, emphasizing the visual confirmation via webcams and the official alert level changes. Tech Times provides a deeper technical analysis, highlighting that the irregular recharge is not due to instrument noise from Hurricane Lala but reflects actual ground deformation. Tech Times notes that this is the first intrinsically irregular pause in the cycle, suggesting potential changes in the magma supply system. HVO, as cited by all sources, maintains a cautious forecast, widening the window due to the stop-and-start nature of the inflation, while noting that the eruption remains confined to the national park with no threat to communities outside the crater.

Why it matters

The irregular recharge pattern challenges the previously reliable forecasting model for Kīlauea’s eruptions, which had been predictable since early 2025. This uncertainty affects aviation safety, as the ORANGE aviation color code alerts pilots to potential ash and gas emissions. Additionally, the widened forecast window complicates planning for visitors and researchers, as the precise timing of Episode 55 remains uncertain. The event also highlights the dynamic nature of volcanic systems, where even predictable patterns can shift due to internal magma supply variability.

What to watch

HVO will continue monitoring summit inflation via tiltmeters and webcams to determine if inflation resumes, which would trigger Episode 55. If deflation continues, the forecast window may extend to September 13. HVO will issue a new Volcano Activity Notice when fountaining formally begins, potentially raising the alert level to WARNING and the aviation color code to RED. Visitors should monitor HVO updates and adjust plans accordingly, as conditions can change rapidly during the precursory phase.