The climb from the Emerald Lakes to the rim above Red Crater was indeed the hardest part of the entire crossing - about 400 vertical feet (125m) of steep, loose gravel and scree. Despite the tiring nature of hiking uphill on such loose material, we all did it in fairly short order. Lori certainly dispatched it with relative ease, despite her earlier reservations.
Some of the other hikers with us on the slope fared more poorly. Some were clearly not at all prepared for this sort of loose, steep terrain, and you could see it in both the type of footwear they were wearing (loafers, flip-flops, that sort of thing) and in their body language (some looked quite nervous). For some, it was probably the trickiest terrain they had ever stepped foot on.
Beginning Red Crater Climb
The scree-slog ended with our arrival at the 6150-foot (1875m) summit of Red Crater. From here, a commanding view in virtually all directions presented itself. Mt Doom (Ngauruhoe) now rose high into the sky only 2km distant. Back to the northeast, from the way we had just come, we had a bird's eye view down over the Emerald Lakes, Central Crater, Blue Lake, and - in the very far distance - Lake Taupo. Immediately beside and below us was the dark reddish interior of Red Crater, full of strangely formed flows of different lava layers.
An optional side trail branched off to the north here, following an easy ridgeline for a couple of kilometres to the actual highpoint of Mt Tongariro. There wasn't any sort of interest in doing this sidetrip from the members of our group (so we didn't).
After taking many portraits against the various scenic backdrops, we headed a little ways over the high point to find a spot out of the rather chilly breeze that was blowing. Here we stopped for our official lunch break. We relaxed with the pleasant knowledge that all the hard work was now done. From here, it was almost entirely a downhill walk to the far end of the crossing.
The first part of the downhill walk from Red Crater was not at all like the loose, gravelly ascent we had just completed up the opposite side. Instead, a firm trailbed led down along a craggy ridgeline - in a few places, protected with ferrata-like wires. This ridgeline led down to another wide, flat area - the South Crater of the Tongariro Massif.
The track then led west across the floor of South Crater. The crater's floor was quite smooth and flat. It was very similar to a dry lakebed such as you might find in a desert locale, such as the US southwest. Towering ever closer as we walked was Mt Ngauruhoe. We were now close enough to see that the slopes of Mt Doom were scoured with many streaks from hiker traffic.
A wide breach in the western rim allowed us to exit the South Crater without any significant uphill. A new vista opened up to us here, down into a long, lava-filled valley - the Mangatepopo Valley. At the far end of the valley, just beyond its mouth, waited the carpark and the trail's end.
We walked past the sign marking the off-trail scramble route to the summit of Mt Ngauruhoe. I had harboured the idea of climbing the peak, but no one else was particularly interested in the extra 3km distance and 600m (2000') of elevation gain. It would have made for a difficult and long day, and whoever didn't go would have had to wait for a long time at the trailhead. Another time, I guess.
With our feet now getting a little trail-weary, we plodded down into the Mangetepopo Valley, happy for the return of carefully curated trail. Pu, myself and Caroline opted for the short side visit to a spring in the valley wall.
The clear water from the spring formed into a pleasant little stream, accompanying us pleasantly as we walked down the Mangatepopo Valley. Long stretches of superbly-constructed boardwalk made for easy walking through fields of knobbly lava.
Extensive Boardwalking Returns