Hawaii: Kīlauea volcano is erupting – Aviation Color: RED – Volcano alert level: WARNING

Kīlauea volcano is erupting. At approximately 3:20 p.m. HST on September 29, 2021, the USGS Hawaiian Volcano Observatory (HVO) detected glow in Kīlauea summit webcam images indicating that an eruption has commenced within Halemaʻumaʻu crater in Kīlauea’s summit caldera, within Hawai‘i Volcanoes National Park.

Webcam imagery shows fissures at the base of Halemaʻumaʻu crater generating lava flows on the surface of the lava lake that was active until May 2021.

The US Geological Survey Hawaiian Volcano Observatory (HVO) is elevating Kīlauea’s volcano alert level to from WATCH to WARNING and its aviation color code from ORANGE to RED as this new eruption and associated hazards are evaluated.

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Kīlauea volcano started erupting at approximately 3:20 p.m. HST on September 29, 2021. Pictures via Twitter

Hazard Analysis

The activity is confined to Halemaʻumaʻu and the hazards will be reassessed as the eruption progresses.

This new eruption at Kīlauea’s summit is occurring within a closed area of Hawai’i Volcanoes National Park. Therefore, high levels of volcanic gas are the primary hazard of concern, as this hazard can have far-reaching effects down-wind.

Large amounts of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—are continuously released during eruptions of Kīlauea Volcano.

As SO2 is released from the summit, it will react in the atmosphere to create the visible haze known as vog (volcanic smog) that has been observed downwind of Kīlauea.

Vog creates the potential for airborne health hazards to residents and visitors, damages agricultural crops and other plants, and affects livestock.

Additional hazards include Pele’s hair and other lightweight volcanic glass fragments from the lava fountains that will fall downwind of the fissure vents and dust the ground within a few hundred meters (yards) of the vent (s). Strong winds may waft lighter particles to greater distances. Residents should minimize exposure to these volcanic particles, which can cause skin and eye irritation.

Other significant hazards also remain around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes within the area closed to the public. This underscores the extremely hazardous nature of Kīlauea caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since late 2007.

The current eruption was preceded by dozens of earthquakes and a strong inflation:

Visitors to Hawai’i Volcanoes National Park should note that under southerly (non-trade) wind conditions, there is potential for a dusting of powdery to gritty ash composed of volcanic glass and rock fragments. These ashfalls represent a minor hazard, but visitors should be aware that dustings of ash at areas around the Kīlauea summit are possible.

Alert levels and aviation color warnings

Alert levels from USGS

USGS Alert levels during volcanic eruptions
USGS Alert levels during volcanic eruptions. via USGS

Aviation color codes by USGS

Aviation color codes during volcanic eruptions
Aviation color codes during volcanic eruptions

HVO is in constant communication with Hawai‘i Volcanoes National Park as this situation evolves.

The opening phases of eruptions are dynamic and uncertain. HVO continues to monitor the volcano closely and will report any significant changes in future notices.

Stay informed about Kīlauea by following volcano updates and tracking current monitoring data on the HVO web page: https://www.usgs.gov/volcanoes/kilauea/volcano-updates.