A lot of hunters and tourists in the Rocky Mountain region would love to be within shooting distance of an elk. Every year in Greater Yellowstone, a fortunate number of legal hunters outside the world’s first national park, as well as camera-laden visitors within its boundaries, get their wish, yet sometimes elk target humans instead.

I eased into a warm side pool at the confluence of the Boiling and Gardner rivers one early April afternoon. It had snowed several inches the night before, yet it did not stop about 50 elk from also showing up, seeking relief and relative warmth on a windy, overcast day. American dippers, or water ouzels, flitted up and downstream, their slate gray forms blending in perfectly with the rocks from where they bopped and dipped for insects in the roiling waters.

Snow-clad sagebrush and Rocky Mountain junipers slowly dropped bunches of wet, gloppy snow that had fallen the night before, as the small herd of elk cows, yearling calves, and spike bulls foraged on the other side of the confluence. They coveted this area-for the soothing steam rolling off the river, for the narrow green ribbon of grass just beginning to sprout along the snow-free banks, and for the reprieve it offered from eking out a living in still deep snow at higher elevations on Yellowstone’s Northern Range. Nonetheless, between wisps of steam clouds, we kept a cautious eye on each other.

I settled deeper into a warmer pool, letting the hot water massage muscles sore from backcountry skiing the day before, relief and release freely and generously provided by nature. From time to time, I could hear elk on the opposite shore call to each other as they grazed.

One cow elk tensed up and swung its head sharply, stomping the ground in warning to a yearling encroaching on its feeding area. The yearling cautiously backed down, moving a few yards farther away, yet it continued shadowing her closely, perhaps hoping that she would forfeit her apparently easier and more abundant grazing spot.

I drifted back into a primordial world, convalescing in these thermal waters. The wind picked up. Swirling, sulfur-scented clouds of steam continually enveloped me before cascading downstream. Occasionally I noticed a few elk carefully negotiating the river, obscured by the rolling fog. Their migration had an eerie, ghostlike feel to it, like a dream, as other elk appeared and then disappeared in the mist.

Suddenly I heard and then saw movement much closer to where I was relaxing in the Boiling River. It was dark brown. It smelled awful, and it was unnerving. Worst of all, it was coming closer.