Hawaiian Volcano Update: Kīlauea Eruption’s Ep.47 Completes, Ep.48 Ahead - May 21, 2026
Following the expected 9-day pause, and 12 hours of precursory activity marked by around 75 overflows from only the south vent, episode 17 of Kīlauea’s ongoing summit eruption began at 3:27 PM on Thursday afternoon with a vigorous lava fountain from only the north vent. The north vent reawakened around 2:35 PM, building to a vigorous low dome fountain by 3 PM and to a peak of 650 feet or 200 meters high by 5 PM, while the south vent only spatterred and jetted similar to the previous 3 episodes. The 9 hours of vigorous fountaining and estimated 5.2 million cubic meters of lava erupted were also within the recent trend. Monitoring instruments show recharge ahead of another expected episode, with the latest USGS Hawaiian Volcano Observatory forecast window set between Sunday, May 24 and Tuesday, May 26, barring any natural delays.
Although episode 47 occurred during the trade wind pattern, wind speeds around Kīlauea summit dropped into the evening, allowing the volcanic plume to rise vertically and causing sparse tephra up to 3 inches or 5 centimeters in size to fall at the Uēkahuna and Keanakākoʻi overlooks in the National Park. The plume rose to 20,000 feet or 6,000 meters above sea level, and catching upper level winds from the southwest, carried smaller volcanic particles (ash and Pele’s hair) to communities to the northeast including Mauna Loa Estates, ʻŌhiʻa Estates, Volcano Village, and Royal Hawaiian Estates.
According to recent National Weather Service discussion, “breezy to strong trades will likely continue through early next week” during which episode 48 is expected. Trade winds generally carry volcanic emissions and tephra to the southwest into the closed area of Hawaiʻi Volcanoes National Park, reducing the impact to nearby communities, although a pattern similar to episode 47 could also be possible. During the onset of each episode, emissions are at their peak on the order of 200,000 tonnes of SO2 per day, and can be carried substantial distances across the south side of the island, wrapping around to the Kona coast under current conditions. Both during and between episodes, vog and tephra remain the most common hazards for island residents, and the usual precautions and preparations apply, especially for those with respiratory sensitivities – more information at https://vog.ivhhn.org/.
As usual, we summarize the monitoring signals, imagery, and reports available courtesy of the USGS Hawaiian Volcano Observatory as well as our broader community, annotating the presentation on-screen as we go and discussing live viewer questions.
