Ping-Ko Chiu


Software Engineer,
Location Technologies @ Apple
pingkochiu [at]

17 May 2022

Mauna Loa Trail

by Ping-Ko Chiu


The Mauna Loa Trail is a 38.2mi hike from the lookout point at 6.6k ft to the summit cabin at 13.6k ft. We completed the trail in four days — first day from 6.6k ft at the Mauna Loa Lookout to the Red Hill Cabin at 10k ft in 7hrs, second day to Summit Cabin at 13.6kft in 11hrs, and the third and fourth day back down in reverse order in 8hrs and 4hrs respectively. Each day, we aimed to get to our destination by 5pm so we have 2hrs of sunlight to fetch water and cook our meals. We went to bed at around 8PM everyday.

We navigated with cairns, stacked rocks along the trail. We have GPS but we would not have been able to navigate with it. GPS can be used to check distances and make sure we dont go too far off course but it would be completely ineffective for navigating the twisty turny terrain. The cairns are placed so that we can see the next one if you stand near the current one. It was like playing connect the dots. Leading the group is a unique experience as you would have to constantly look for the next cairn. This is as opposed to following the person in front of you and staring at the ground. I prefer leading as it gives me a better sense of orientation.


There was lush vegetation at the Lookout Point where we started the hike. As we ascended, the vegetation starts to become sparse. At 8k ft, we saw the last tree, and at 9k ft onwards, there was no sign of life.

The lava rocks came in different colors and shapes. Some are ube colored, some like oreo cookies, some like red bean dip, and some are grey like sesame paste. We can see how they came from different eruptions as one would overlay another. Lava doesn’t flow evenly so some spots would be left out and the the layer below will become visible. Sometimes the meeting point of the two layers would extend on for miles. We would often hike between the two layers with one layer to our left and another to the right.

Some of the terrain is smooth, but some is extremely uneven, full of fist to basketball sized sharp rocks. Hiking on the uneven terrain is difficult and slow. We were warned that the last mile to the summit cabin is the most difficult but we found it to be about the same as mile 7-8 from red hill cabin.

These rocks also make different sounds when we hike on them. The pores and fist sized volcanic rocks would make high pitched clangs similar to when charcoal is being thrown into the grill. Some rocks are cracked into big slabs. The whole slab can become a seesaw when you walk on them and make a thud when you move your weight onto the other end of the seesaw. At the caldera, the surface was flat but still has a sandpaper like texture. Walking on them was mostly quiet but you’d still hear the grip your shoes have on the rocks.

One thing that constantly surprised us was how far we can travel on our two feet. Sometimes we would see our destination in the far distance only to reach it in just an hour or two.

The terrain on the second day was absolutely brutal. I remember feeling thankful for those that charted the way and laid the cairns. At some point i was thinking about what to do if there is an emergency. What if someone has a stroke or faints and hits their head. I didn’t know at the time that Mike and David’s InReach could call helicopters. Without this knowledge, I was left thinking to myself that the only way is for us to hike back several miles until there is signal to call for rescue.


Ranger Greg told us that the cabins were built in the 1920s. They would only maintain it every 30 years or so. The cabins were clean. There wasn’t much to the cabin besides four walls that shield us from the wind and bunks with foam mattresses for us to sleep on. Both the Red Hill Cabin and the Summit Cabin were clean when we arrived and we cleaned up before we left.

Next to the cabins are water catchment tanks. I’ve read elsewhere that the water can get quite nasty but it was nice and clear for us. I am guessing thats because there was fresh rainfall before and during our hike.

The toilet at the Summit Cabin is one of the highlights of the trip. The more modern toilet was out of service so the only other option was a little three walled wooden shack with a toilet seat positioned directly over a three meter deep crack. There was probably decades, if not a century, of human excrement in that crack. Given how inaccessible the crack is, I kind of doubt that it is cleaned regularly or at all. Since the toilet doesn’t cover the entire crack, the wind can blow through the toilet seat into the wooden shack, giving you a bottom up breeze with a hint of what your predecessor left behind. The nice thing about this toilet is that it has a view over the entire caldera, the best view I’ve ever seen on a toilet. I spent longer than I had to on the toilet, despite the chill and the smell, just to soak in the view for a bit longer.


We were all taking Diamox to help ourselves acclimate to the altitude. Going from sea level to 13.6k ft in two days exposes us to the risks of altitude sickness. Having had altitude sickness before when I was a kid made me a little nervous. I could feel the air thinning as we reached 9k ft elevation. A deep breath at high elevation just doesn’t feel as fulfilling as it is at sea level. At 12k ft elevation on day 2, I started to get slight headaches periodically. I would completely recover with a small break but every 0.25mi after a break, the headache would set in again. It went on like this for a few more times.

At the summit cabin at 13.6k ft, while sitting completely still, I received a notification on my Apple watch indicating that my heart rate was at 120bpm. This got me a little alarmed because my resting heart rate at sea level is around 50-60bpm. I tried to do some breathing exercises before I went to bed and it brought my heart rate down to 100bpm but not any lower. 100bpm is like a light workout at sea level. I could not sleep well for the entire night — I was lying completely still but I felt restless. I remember feeling sorry for my heart, having to work extra hard just to cope with the altitude.


tags: Travel