A Hike to Ka'au Crater

Ka'au Crater

by Dayle Turner

Of the craters on the island of Oahu, the most familiar to residents and visitors are Diamond Head and Koko Head. Fewer know about Ka'au, a small crater tucked against the spine of the Koolaus. Early on this late-October morning, I had the good fortune to join 42 energetic nature trekkers on a Sierra Club-sponsored hike to this beautiful geological landmark in the upper reaches of Palolo Valley.

According to Hawaiian legend, Ka'au was formed as a result of an unsuccessful island-unification effort by the demigod Maui. While attempting to consolidate Oahu and Kauai into a single land mass, Maui saw his efforts end when the magic fishing line he had been using suddenly snapped. The huge hook affixed to his line sailed skyward, landing in upper Palolo and forming Ka'au Crater.

Geologists tell a different story. In the scientific version of the genesis of Ka'au, the crater was formed from an explosive upswelling of volcanic material from deep within the earth's core. In geological terms, Ka'au is classified as a tuff cone, its foundation composed primarily of porous rock formed by compacted volcanic ash and dust.

The trail to Ka'au begins in a quiet neighborhood at the end of Wai'oma'o Street on the Maunalani Heights-side of upper Palolo Valley. The trek leaders--Gerald Toyomura, Linda Onomoto, and Peter Klein-- made sure everyone had signed both the club's hike roster and a permission form supplied by the Board of Water Supply. Affixing our John Hancocks to the latter was necessary because we'd be entering kapu watershed land.

After a quick roll call, we shoved off at a few minutes before nine. The Sierra Club policy requires that all its hike participants stay with the group. In other words, by signing the hike roster, we had agreed to stay between the lead person (Gerald, for today's hike) and the trailing "sweep" (Linda) for the duration of the outing.

And so we proceeded, three-and-half dozen backpack-equipped trekkers in a safari line reminiscent of the kind used in those olden day jungle flicks. For the first 15 minutes, the trail meandered mauka along Wai'oma'o Stream, the same watercourse where a woman was tragically swept downstream and killed during a flash flood a couple months before (she had been hiking on the same trail we were on). After five stream crossings (the water flow on this day was a trickle), we reached a junction where we could either turn right and continue upstream, eventually ascending to the crater via a three slippery waterfall sections, or turn left, gaining the ridgeline via a switchback trail. Our leaders opted for the left route up the switchbacks.

We huffed our way upward to gain the ridgetop, the sound of cheerful conversation penetrating the quiet serenity of this otherwise peaceful milieu. Overhead, a cover composed mostly of guava trees obscured our views of overcast Oahu skies. The temperature probably hovered in the mid-80s with the humidity nestled near a sweat-inducing 90 percent.

One of the benefits of Sierra Club outings is that hike leaders (and many participants) are knowledgeable about Hawaiian flora, fauna, and other hike-related information and these folks are quite open about sharing their mana'o. Gerald, for instance, pointed out some ancient Hawaiian agricultural sites along Wai'oma'o Stream, and Linda and Peter (and at least half a dozen other hikers) brought our attention to an array of plants, such as 'iliahi (sandalwood), koa, o'hia lehua, maile, naupaka kuahiwi, 'olapa, hapu'u, hulumoa (Hawaiian mistletoe), kopiko, pilo, a'ali'i, to name just a few.

Because of the informational bent of Sierra Club leaders, frequent rest breaks, and the number of people on the outing, we hiked along at a pace much slower than one would proceed if hiking alone or with a smaller group.

About 90 minutes after we had begun, we had completed our first major climb of the day and gained our first view of the crater. Palolo Valley sits between Wa'ahila Ridge to ewa (west) and Mauumae Ridge to Kokohead (east), and Ka'au is nuzzled against the valley's back wall with the peaks Olympus, Palikea, and Lanipo jutting out prominently from left to right along the summit spine.

The crater itself, according to Gerald, is approximately a third of a mile in diameter. Its swamp-like floor was a couple hundred feet below us, and except for a few pockets of visible standing water, was covered almost entirely with reedy vegetation. While hiking through the crater is possible (the ground there is supposedly very mushy and at one time had been under water), doing such wasn't on today's agenda.

The ridge we had climbed extended to the crater's southeastern corner. From there, the trail we followed swung ewa (west), following Kaau's southern rim. At around 11 a.m., we reached a clearing beneath a skyscraper-like powerline tower. We took a 10-minute break there, resting, glugging down water, and watching as clouds started to amass on what had been a previously unobscured summit.

Our short respite complete, the group, save for three folks who decided to sign off and head back down the mountain, pushed on toward the summit. To reach the top, we followed a trail that proceeded along the ewa (west) edge of the crater, first dropping a hundred feet or so into a saddle, and then climbing fairly steeply up a finger ridge (another steeper trail to the summit follows the crater's eastern side, topping out at Palikea). The higher we ascended (we did so at a slow pace because of our numbers and the angle of the grade), the more spectacular the view of the crater. "This is so cool," remarked the chap in front of me while clicking off a couple of snapshots.

Despite the lingering humidity and the increasing congregation of clouds upslope, cool indeed it was.

At just past noon, we reached the summit of the Koolaus at a point between Mount Olympus and Palikea. The elevation was probably between 2,400 and 2,500 feet. The ridgetop, about fifteen feet wide and topped by another high powerline tower, was our designated lunch spot. Clouds denied us views of the windward side (if visibility were clear, we would have been looking down on Mount Olomana and the Kailua-side of Waimanalo). Townward, a pasty haze shrouded the urban sprawl of Honolulu proper, its tentacles clearly extending deeper and deeper into the undeveloped reaches of Palolo.

Following a personal tradition I've instituted when attaining a hiking milestone--reaching the summit of the Koolaus, view or no view, is always a cherished occasion--I hoisted my water bottle skyward and took a celebratory swig.

At 12:30, not wanting to hang out at the summit till 1 p.m. when the group would begin its return leg, I asked Linda for permission to sign off and descend alone. She consented and after thanking her for helping lead the hike, I headed off.

Just like there were benefits to hiking with the group, trekking alone has its merits. For one, I can proceed as quickly or slowly as I like, an important consideration for me especially when descending a steep ridge (I get a bit distracted and paranoid when someone's right behind me on a precipitous descent). And while I enjoy the company of others in the backcountry, I also relish times sorting through my thoughts when tramping alone in the mountains.

And so it was as I picked my way downslope, with the magnificent Ka'au now to my left instead of right. When I reached the powerline tower break spot, I paused for a moment to gaze down the valley to the area of upper-Palolo (Myrtle Street) where my grandparents had lived, recollecting how as a youngster I had stared with wonder at the very mountains I had just journeyed into.

With those long-ago memories dancing in my thoughts, I pushed on, striding quickly and carefully along the trail, retracing my steps down the ridge and switchbacks, crossing Wai'oma'o Stream the same handful of times, and making my way to my car all in less than half the time taken to ascend with the group.

In all, I invested just under five well-spent hours on this Sierra Club-sponsored trek. Much aloha is extended to Gerald, Linda, and Peter for a well-organized adventure.

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