I've got a few more stories to tell from Hawai'i... Today I'd like to share the tale of a backpacking trip that my friend Lily and I took along the northern coast of the big island. From the road's end at the Pololu Overlook, we descended into the Pololu Valley, across its excellent beach, then up the adjacent ridge to the east, down into the next valley, up another ridge (and further east), and then down into the third valley, where we camped.

The route is shown on this Google "My Maps" map:


Here's a look eastward into that final valley:


Descending into the final valley:


The view from our campsite:


The substrate of our campsite: a poorly-lithified conglomerate:


The thing that stands out in my mind most about this excursion was a landslide scar that had cut off the trail at one point. This landslide occured in the middle valley (between Pololu and our campsite valley). The landslide scar is nice and visible in the lower-left of this Google Maps image:


It happened in 2006, triggered by the big earthquake that struck the big island that year. It was one of several landslides that were set off by that shaking. (Wikipedia has a nice "live-action" photo of another cliff collapsing up the coast at Waipio.)

Here's the landslide scar viewed from the east, looking west (on our hike back towards Pololu):


Another shot from the same perspective shows the run-out of debris below the source:


The tricky thing about this was that we had to get past this landslide, since it wiped out the trail. On our way in, we somewhat stupidly climbed down the face of the landslide itself, gingerly picking our way down the steep slope, so we didn't trigger any further mass wasting. Here, for instance, is a poorly-put-together composite photo showing Lily descending into the valley:


(On the way out, we found some ropes in the vegetation next to the slide, and hauled ourselves up those rather than getting on the slide surface again.) But on the way in, when we got to the bottom, we weren't sure where the trail was, and plunged through some dense bamboo forest. I felt like I was in LOST, where the characters are perpetually fighting their way through similar vegetation:


Eventually we found the trail, and continued along. Because of the landslide blocking access, this part of the trail hasn't been used as much for the past two years. Lots of pandanus leaves had been shed off and blanketed some parts of the trail. Hiking across these dried pandanus leaves was a noisy affair:


On the eastern side of the ridge between "Landslide Valley" and "Campsite Valley," we saw this two-inch-wide crack opening up along the trail, parallel to the ridge/valley trend. The edge of the ridge was about twenty feet away towards the east (direction my boot toe is pointing). Certainly something like this portends a future episode of mass wasting...

Labels: hawaii, landslide, mass wasting, sediment, travel