One of our favorite attractions in Hawaiʻi Volcanoes National Park has reopened at long last! After being closed for nearly a year due to pandemic-related precautions, the park reopened Nāhuku (Thurston Lava Tube) on March 26, 2021.     

A 500-Year Old Formation

Formed more than 500 years ago, Nāhuku was first publicized by Honolulu publisher Lorrin Thurston in 1913. In Hawaiian, Nāhuku means “the protuberances,” which is a likely reference to the lava stalactites that once covered its ceiling before being removed by visitors as souvenirs. 

So where exactly did this lava tube come from? From the flow of viscous lava! 

The cooler lava on the surface solidified faster than the lava underneath, forming a crust-like roof over the rest of the still hot, flowing lava. When the flow stops, there is a cave left behind as a lasting reminder of where the lava once flowed. 

A History of Closures

During the Kīlauea eruption in 2018, cracks formed in the Thurston Lava Tube and large rocks fell from the ceiling. After the eruption, Hawaiʻi Volcanoes National Park closed the lava tube as a safety precaution. 

Two crack monitors were installed, and a low-hanging rock was marked off to prevent head injuries. Data from the monitors reveals little change in the cave’s structural integrity.  

In February 2020, the park marked off a potentially dangerous low-hanging rock, installed crack monitors, and deemed it safe to reopen the lava tube… only to close it a mere month later when the pandemic struck.

The New and Improved Lava Tube

Although we missed strolling through the ancient underground tube on our visits to Hawaiʻi Volcanoes National Park, something magical happened while it was closed to the public for a year:

On the tube’s walls, colonies of white microbial matter began flourishing. And the long, fragile roots of ʻōhiʻa trees growing above the lava tube now extend all the way to the ground in some areas of the cave! 

A Tip from Tutu: The lack of stalactites in Nāhuku is a reminder of the importance of protecting the fragile tube’s ecosystem. Please refrain from touching the walls of the cave and the roots growing in it. 

Explore the Thurston Lava Tube

Enjoy the scenery as you pass through a lush rainforest, serenaded by the song of native birds before entering the 0.3 mile-long underground tunnel created by the river of 2000 degree-Fahrenheit lava that once flowed here. 

On the other side, you’ll continue following signs through the native rainforest. The new signs are intended to keep everyone moving safely in the same direction. If you’re not moving counter-clockwise, you’re going the wrong way! 

Up for a longer, more scenic hike? In one hike, you can explore Devastation Trail, Byron Ledge, the Kīlauea Iki loop, and Thurston Lava Tube! 

For this adventure, pack some snacks, water, and a rain jacket. And be sure to wear a mask, as well as a pair of sturdy hiking boots or trail runners for this moderate hike. 

Since the Kīlauea Iki Overlook can get crowded, park at Puʻu Puaʻi or the Devastation Trailhead, and follow the one-way signs through the lava tube and along the enchanted rainforest trail. You’re in for a six-mile round-trip hike from Devastation Trailhead (including the Kīlauea Iki loop). If you embark from Puʻu Puaʻi, it’s only a mile longer. 

As there are risks involved with hiking any lava tube (think low rock ceilings, tripping hazards, rockfall, standing water, and dimly lit paths), take care when walking through the lava tube. 

Although Nāhuku is open 24 hours, we prefer visiting the lava tunnel before 9 am or after 4 pm to avoid the crowds and enjoy a socially-distanced adventure. Bring a flashlight or headlamp if visiting between 8 pm and 8 am, when the lava tube is not lit. 

And if you’re brave enough, we recommend turning off your light or lamp for a minute or two, standing still, and observing the sounds and smells of the ancient lava tube.

Stay in a Volcano Heritage Cottage

Looking for the perfect headquarters for your Hawaiʻi Volcanoes National Park? The Thurston Lava Tube is only minutes away from our historic cottages in Volcano Village. Book a stay at one of our cottages in Volcano today and get ready for one memorable Big Island adventure!