Walking on the roof
Yellowstone sits over a caldera: a magma chamber close enough to the surface that groundwater sinking down comes back up boiling. Everything the park is famous for — the geysers, the hot springs, the mud pots, the smell — is that one fact expressed in different ways.
What surprises you on the ground is how ordinary the setting is around it. It is not a moonscape. It is pine forest and river valley and grazing bison, with holes in it where the earth is boiling.
Norris
Norris Geyser Basin is the hottest and the oldest of the basins, and the most changeable. Features there do not settle into a routine the way Old Faithful has; they appear, shift, go quiet, and come back. The ground is bleached pale, steam comes off it in every direction, and the boardwalk exists because walking on it directly is not survivable.
Norris also holds Steamboat, the tallest active geyser in the world. Its major eruptions can throw water more than three hundred feet up. It is entirely unscheduled — it has gone years between events, then erupted dozens of times in a season. You do not plan around Steamboat; you either happen to be there or you don't.
Dragon's Mouth
At Mud Volcano, further into the park, is a spring called Dragon's Mouth. It sits back inside a cave-like opening in the hillside, and rather than bubbling politely it surges — water sloshing out of the cave mouth in waves, with a low booming noise coming from somewhere inside the rock.
The sound is the part that stays with you. Steam and water are being forced through a confined space underground, and the hillside is broadcasting it. It is the single most obviously alive thing in the park.
Water that cannot decide
Driving through, the road crosses the Continental Divide — the line where the continent decides which ocean its rain belongs to. East of it, water ends up in the Atlantic. West of it, the Pacific.
At one of the passes there is a small lake sitting directly on that line, and it drains both ways at once: part of it goes to one ocean and part to the other. A pond with two destinations, in the middle of a road, with nothing marking the occasion but a sign.
The oath
Most national parks run a Junior Ranger programme: children work through an activity booklet, take an oath, and are given a badge. We have collected a fair number of them by now. None of the others does it the way Yellowstone does.
Here it is a proper ceremony. The kids are seated in a row of chairs at the front. The parents stand along the side and watch. A ranger stands before them and speaks the oath out loud, and the whole row says it back.
Nothing about it is hurried and nobody treats it as a formality, which is the entire difference. It is wonderful to watch.
Mountains with no run-up
An hour south, Grand Teton does something completely different and just as abrupt.
Most ranges build up to themselves — hills, then bigger hills, then peaks. The Tetons don't. They come straight up off the flat valley floor with no foothills whatsoever, a wall of rock starting where the grass stops. It looks wrong the first time you see it, like a stage backdrop set too close.
The reason is that a fault runs along the base of the range: the mountain side has been lifted and the valley side dropped, and the two are still moving relative to one another. What you are looking at is not erosion having carved a range down, but a block of crust standing up out of the ground — and the flat floor in front of it is the other half of the same movement, going the other way.
We walked into Cascade Canyon, which is where the second half of that story is written. The trail leaves from Jenny Lake, climbs past Hidden Falls and Inspiration Point, and then turns in between the peaks — and the canyon it enters is a clean U in cross-section, flat-floored with steep walls rising either side. Rivers cut V-shaped valleys. Glaciers cut U-shaped ones. The fault pushed the block up; the ice then carved it into the shape you actually see.
Seven miles or so up the north fork, above the treeline, is Lake Solitude — a tarn lying in a bowl the ice scooped out of the head of the canyon, with the Grand Teton standing over it from behind. It is the same mountain everyone photographs from the valley floor, seen from the wrong side and a great deal closer.
We camped at Mammoth up in the north of Yellowstone, and at Colter Bay under the Tetons — which meant waking up two mornings running to entirely different explanations of what mountains are.