Hike Journal - Nāpau Trail - April 26, 2004

Hike Journal - April 26, 2004
by Annika

The attached document recounts our experiences along the Napau Trail. The photos associated with the text are listed beneath each heading. Captions for some of the photos are highlighted.
 
Napau Trail
Early on the misty morning of Monday, April 26, 2004, twenty-one geology students and two of their professors met in front of the famed fireplace at the Volcano House hotel. After discussing the day’s hike and making sure everyone had the necessary supplies (plenty of water, respirator, sunscreen, etc.), our convoy of SUV’s headed down Chain of Craters Road to the Mauna Ulu parking area. By 8:30 am, we were ready to follow the much-anticipated Napau Trail.

According to the National Park Service, the Napau Trail is a challenging, 10-mile (one-way) hike from the Mauna Ulu parking lot to the Pu’u O’o (active vent) area. Other points of interest include:
  • Pu’u Huluhulu Cone
  • Lava flows from Mauna Ulu
  • Makaopuhi Crater
  • Napau Crater
 
What to Expect
When preparing to hike the trail, plan to spend all day hiking across rough lava terrain and through muddy rain forests. The park service requires hikers to obtain a backcountry permit before entering the area and recommends carrying 4-6 quarts of water per person. Expect rain and wind, and stay on the trail to avoid brittle lava that cracks easily.
 
Amber, Camille and Sarah are well prepared
Amber, Camille and Sarah are well prepared

Trailhead
The trailhead leaves from the Mauna Ulu parking lot, about 7 miles from the Visitors Center. After shuffling vehicles, we finally left the parking lot at 8:30 in the morning.
 
Laura and Melissa anxious to hike
Laura and Melissa anxious to hike
 
Rental SUV's take the place of the infamous geology vans
Rental SUV's take the place of the infamous geology vans
 
From the Trailhead
For the first section of the hike, we followed yellow markers attached to the lava surface.
 
Pointing out Mauna Ulu to the East
Pointing out Mauna Ulu to the East

Pahoehoe and Kipukas
The first part of the trail crosses pahoehoe lava from eruptions in the early 1970’s. “Pahoehoe,” the Hawaiian term for “ropy,” gets its name from its smooth, billowy texture. Ohia trees are the initial colonizers of these lava flows. The trail also leads through the occasional kipuka, an “island” of vegetation surrounded by younger flows.
 
Lava fields from the 1970's

Lava Trees
West of Pu’u Huluhulu, numerous lava trees and tree molds are scattered along the trail. Lava trees are formed when lava flows surround a standing tree. The lava level later recedes, leaving lava trees as tall monuments indicating the highest lava level, and the hollow center marking the size of the tree. Tree molds are the horizontal equivalent. When lava surrounds a downed tree, steam from the tree quenches the lava, often leaving the imprint of charred wood.
 
Riley precariously looks down into a lava tree
Riley precariously looks down into a lava tree

Pu’u Huluhulu
About one mile from the trailhead, the trail splits and leads up Pu’u Huluhulu, (“Hairy Hill” in Hawaiian). It required briefly hiking uphill, but the shade of the large trees that give the hill its name was welcome after walking across the sparsely vegetated lava.
 
The trail to the overlook breaks off to the north
The trail to the overlook breaks off to the north

The Overlook
We reached the viewing area at the top of Pu’u Huluhulu at 9:00 and took a few minutes to look around.
 
To the south lies the vent of the Mauna Ulu shield, which erupted from 1969-1974
To the south lies the vent of the Mauna Ulu shield, which erupted from 1969-1974
 
Mauna Loa, one of the main shield volcanoes, is seen to the west, partly mantled in clouds
Mauna Loa, one of the main shield volcanoes, is seen to the west, partly mantled in clouds

A View of Pu’u O’o
Pu’u O’o was visible along the rift zone to the east. The distant vent could be seen spewing sulfur and steam.
 
The shield vent visible just to the right of Pu‘u O‘o is the prehistoric Kane Nui O Hamo
The shield vent visible just to the right of Pu‘u O‘o is the prehistoric Kane Nui O Hamo

Pu’u Huluhulu to Makaopuhi
Seeing Pu’u O’o in the distance gave us a renewed sense of how far we still had to hike, and we headed back down Pu’u Huluhulu and rejoined the main Napau Trail. The second segment of the trail leading to Makaopuhi continued east across pahoehoe from the 1973 and 1974 Mauna Ulu eruptions.
 
The trail is marked by ahu, or small cairns of piled rock
The trail is marked by ahu, or small cairns of piled rock

Flow Features
We encountered many lava flow features along the trail, including pressure ridges and plateaus, inflated cavities and low spots in-between.
 
Sarah walks through a depression in the flows
Sarah walks through a depression in the flows

Steam Fields
Around 10:00, we encountered a large field of steam along the trail. With all the warnings about sulfuric vog, some of us were at first hesitant to walk through the surreal steam, but were soon enjoying the steam bath and taking plenty of pictures. The steam rising from the surface of the lava results from the evaporation of heated rainwater.
 
Students continue to hike through clouds of steam
Students continue to hike through clouds of steam
 
Hiking through steam
 
Camille, Ashley and Elizabeth enjoying the mid-hike sauna experience
Camille, Ashley and Elizabeth enjoying the mid-hike sauna experience

Makaopuhi Crater
We reached the southwest rim of Makaopuhi Crater at 10:45 and took time to enjoy the scenery and pay homage to geologic history. Drilling on the crust of the Makaopuhi Lava Lake began in 1959 and revealed valuable information regarding the sequence of cooling and solidification of lava. The subsurface is still warm, so putting a hand over the drill holes yielded a blast of hot air.
 
Makaopuhi Crater sign
 
Kane Nui O Hamo, a shield truncated by the crater
Kane Nui O Hamo, a shield truncated by the crater
The crater, at a mile long and half that wide, was a breathtaking sight. The floor of the crater is now 430 feet down, but was deeper before being filled in with almost 300 feet of lava.
 
A breathtaking panorama of the crater
A breathtaking panorama of the crater

Into the Woods
After a 15-minute break to enjoy the vista at Makaopuhi, we followed the trail into a rain forest of ohia trees and hapuu ferns. The shade was welcome, but avoiding the mud was a challenge that soon became futile.
 
Ashley and Laura trudging through the mud
Ashley and Laura trudging through the mud
 
Hiker on the trail posing

Pulu Factory
After several miles of nothing but lava and vegetation, the walls of the old Pulu Factory came as an interesting surprise along the hike.
 
Old Pulu Factory sign
 
Old Pulu Factory ruins
 
Only two more miles to Napau Crater
Only two more miles to Napau Crater

The Campground
Around noon we reached a fork on the trail, and followed one side to the primitive campground and the long-awaited latrine (BYOTP). We retraced our steps back to the main trail and were soon on the edge of Napau Crater.
 
Without the overhead canopy, we had a better view of Pu‘u O‘o
Without the overhead canopy, we had a better view of Pu‘u O‘o

Napau Overlook
By 12:30 we were gazing across the expanse of Napau Crater and through the haze toward Pu’u O’o.
 
Hiker looking into the crater
 
Viewing across the crater

We reached the overlook just in time for lunch. After eating and taking care of oncoming blisters, we donned rain gear in response to the darkening skies.
 
The group takes a lunch break

Into the Crater
From the overlook, the trail heads northward and then follows a cascade of a’a lava into the crater. The descent was fairly steep, but only took about ten minutes.
 
Waiting for the rest of the group to reach the floor of the crater
Waiting for the rest of the group to reach the floor of the crater

We followed the trail across the crater floor. The lava flow terrain in the crater is covered with a thin blanket of gravel-like tephra from the explosions of Pu’u O’o. We observed spatter ramparts, abundant reticulite, and a few patches of Pele’s hair.
 
Hiking across the crater floor

Reticulite
Reticulite is a pyroclastic deposit that collects in low spots in the crater. It has a glassy framework and consists of mostly empty space. The light material was very fragile and crumbled in our hands.
 
Closeup view of reticulite (lava foam)
 
A reticulite-loving spider
A reticulite-loving spider

Crossing the Crater
After about an hour, we were hiking back up the crater towards the looming vent of Pu’u O’o.
 
Crossing the crater towards Pu‘u O‘o

Tephra Fields
At 2:00 we were hiking across large fields of tephra ejected from Pu’u O’o. It is important to follow the trail to avoid falling into cracks hidden by the blanket of tephra.
 
Trudging across the tephra in a drifting mist
Trudging across the tephra in a drifting mist

Solidified Flows
As we approached the looming vent, we encountered recent lava flows of glassy basalt spilling out in tongues across the tephra.
 
Students examine glassy shards of lava
Students examine glassy shards of lava
 
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