It starts with the mountains, which hiss and roar like slumbering dragons, spewing heavy clouds of sulphurous steam. The hot springs, thousands of them, stain the landscape with metallic rainbows of seemingly unnatural hues: battery-acid orange; the glittering blue of mineral shower gel. And everywhere, the mud pots are bubbling, frothing, churning.
I’d pulled over at dusk to watch a big male grizzly ambling across Swan Lake Flat towards the road – others noticed too, their brake lights illuminating like fireflies
The land here feels alive, a moonscape of flatulent earth. No wonder Yellowstone inspired a whole new breed of conservation as the world’s first national park.
But it’s clear this place has finally reached its tipping point. Park rangers issued more than 52,000 resource violations in 2015.
Thermal features were broken, protected wildlife was disturbed and car accidents increased by 167 percent, the result of careless behaviour and bear jams.
Yes, bear jams. The traffic so often snarls and halts with the sighting of a roadside grizzly that the phenomenon now has its own name.
Not all visitors are careful, and their impact can have broad repercussions. Starting in 2010, Yellowstone’s trumpeter swans failed to fledge any young. It turns out that people were disturbing the birds when the trails opened in the summer, driving them into open water where it’s much easier for eagles to catch cygnets.
The park extended the closure of the trails until September, but this prompted complaints from frustrated hikers. Today, there are only 29 resident swans left.
Sometimes the animals aren’t the only ones in danger. As visitor numbers increase, the number of accidents do too.
Peak season is now a magnet for newspaper headlines: “Woman gored by bison”, reads one. “Man dissolved by hot spring”, reads another.
The park is so vast that anyone can find their own piece of wilderness
Only days ago, before I hiked up to Trout Lake, I pulled over at dusk to watch a big male grizzly ambling across Swan Lake Flat towards the road. Others noticed too, their brake lights illuminating like fireflies.
Then, a woman exited her truck and shuffled towards the bear. She took out her phone, just a few short strides from the enormous carnivore, turned her back on it and took a selfie. Anything like this would be unimaginable in an African safari park.
Days after my first foray to Trout Lake, I'm about to head back there with Tyrene Riedl, a wildlife guide with an encyclopaedic knowledge of Yellowstone.
Her blonde hair is twisted into a side plait, protruding from a woolly hat damp with melting snowflakes.
The park’s weather is notoriously fickle, and we are caught in a blizzard.