Kilauea Volcano has started erupting again — just four months after the last eruption ended.

A five-month eruption at Halemaumau Crater had completely stopped in May, but just few months later the Hawaiian Volcano Observatory reported that another had begun.

The eruption started Wednesday afternoon and was flowing at a “pretty high effusion rate,” according to Ken Hon, the scientist-in-charge at HVO, who estimated lava “fountains that are 50-100 feet high.”

“Wow — that’s a lot. There’s already 10 meters of lava in the crater as of 5:30 (p.m.),” Hon told the Honolulu Star-Advertiser.

HVO first detected lava glowing at Kilauea’s summit just two hours prior.

“Kilauea volcano is erupting. At approximately 3:20 p.m. HST on September 29, 2021, the USGS Hawaiian Volcano Observatory (HVO) detected glow in Kilauea summit webcam images indicating that an eruption has commenced within Halemaumau crater in Kilauea’s summit caldera, within Hawai‘i Volcanoes National Park. Webcam imagery shows fissures at the base of Halema‘uma‘u crater generating lava flows on the surface of the lava lake that was active until May 2021,” it said in an advisory.

As of Wednesday evening, lava was flowing from two fissures — one on the floor of Halemaumau Crater and one on its western wall. Each of the fissures has numerous vents from which magma is flowing.

“This one is pretty active. It may be a little less active than the one that started last December, but it’s still a good-sized eruption,” Hon said.

John Tarson, owner of Epic Lava, an eco tour company, lives in the Volcano golf course subdivision, and immediately headed to the summit after the eruption started.

“I live across the street, so I heard instantly,” he said.

Tarson went live on Facebook, recording the event early on.

He spoke to the Honolulu Star-Advertiser by phone at sunset Wednesday and described what he was seeing and hearing.

“Right now, as the sun’s going down, the cloud is turning a brilliant orange and the walls of the crater are beginning to glow and light up the bottom of the plume like the flame of a candle lighting up,” Tarson said.

“Right now there’s big fissures of lava coming out from the crusted lava lake, and the gas pressure resembles the sound of a 747 taking off,” he said. “Big whooshing sounds, like you’re taking off of the tarmac.”

There was also increased seismic activity in the area. The U.S. Geological Survey listed about 17 small earthquakes between magnitude 2.5 and 2.9 in the region since Tuesday.

Hon said the earthquakes “started in earnest” at about 2 p.m. Wednesday as the underground magma pushed through cracks in the earth, and they picked up around 30 minutes later. HVO issued a warning for Kilauea Volcano to reflect that it has started erupting.

Volcanic gas and ash are also being released into the atmosphere as a result of the eruption. HVO issued a “red” Aviation Color Code alert on Wednesday, meaning an eruption “is underway or suspected with significant emission of volcanic ash into the atmosphere likely.”

Timelapse of the new summit eruption on Kīlauea volcano.https://t.co/Gb5IDeQTjn

NPS Video/J.Wei pic.twitter.com/f2a7ZSWEIe

— Hawaii Volcanoes NPS (@Volcanoes_NPS) September 30, 2021

Hawai‘i Volcanoes National Park warned the public about hazardous gases that could be especially dangerous to people with heart or respiratory conditions, infants and young children, and people who are pregnant.

Volcanic gases are the primary hazard for the newest eruption, as the lava itself is contained within the crater.

In a social media post, the Hawaii Red Cross stressed: “There is currently NO THREAT to any homes or populated areas of the Big Island. We will continue to monitor the event and update as needed.”

In 2018, a months-long major eruption of Kilauea at Leilani Estates destroyed hundreds of homes and displaced thousands of residents. Before that, the volcano had been slowly erupting for more than 30 years.

Now that Halemaumau Crater has started erupting, thousands of visitors are expected to flock to Hawai‘i Volcanoes National Park to observe the lava glowing at night.

Officials urged the public to stay safe when they do visit, and hope to stop people from entering dangerous areas at the park for photos and videos like they did in December, leading to dozens of citations issued by park rangers.

“We have responded already, like we always do, with … staffing that stays after dark to help with information and keep the public safe,” Jessica Ferracane, spokeswoman for the national park, told the Star-Advertiser.

Tarson says that law enforcement is setting up areas for traffic that is anticipated.

“I’m sure they’re expecting a large crowd,” he said. “Everybody comes. It’s not like people go, ‘I’ve got work tomorrow.’ Everybody comes.”

The COVID-19 outbreak is still the most pressing safety concern, said Ferracane, who also urged visitors to stay socially distanced from each other.

Despite the safety risks that come with a volcanic eruption and the safety risks that people might be to themselves during those eruptions, she said the park will do its best to remain open 24-7.

“We want to keep the park open so everyone can experience this new phase of volcanic activity, but we can only do that if visitors follow the guidelines that keep people safe,” Ferracane said.

With no immediate dangers to people for now, it can be easy to appreciate the natural phenomenon that is the latest eruption at Kilauea.

“Every eruption is awesome in its own way,” Hon said. “These eruptions that stay within the park and are, in particular, confined within the summit area are great because there’s no negative impact on others.”

It’s not clear how long the eruption will last, but history suggests that lava will probably flow for a few weeks.

Tarson said he enjoys bringing visitors to see the volcano.

“It’s kind of like watching children open up Christmas presents,” he said.