"But this cliff is too steep for them to climb back up and so they must return a different way, likely through an ice creek.
This north-south oriented ravine forms a deep gorge that is shaded or partially shaded throughout most of the growing season, resulting in a microclimate that stays relatively cool during the summer, and because of the creek flow and ice formations, is relatively warm in the winter compared to the surrounding area.
At Rainy Pass, the creek was strangely ice-free, a torrent of fast-moving water.
But now the rocky buttress where Rush Creek spills is covered with ice and snow.
Each year the emperor had laborers carve 1000 blocks of ice from frozen creeks in mountain valleys, each block with the dimension of 3 ft (0.91 m) by 3 ft by 3½ ft (1.06 m).
"He would finish the workout and immediately get a protein shake, and then he'd go sit in an ice bath or the creek," Jimmerson told me.
In Oklahoma, a boy sledding near a highway was killed by a truck, and another fell through thin ice on a rural creek and drowned.
Groundwater-influenced oxbow lakes are located along the floodplain of higher-order river and creek channels and receive input throughout the ice-free season from snowmelt-recharged channel fens and sub-surface flow.
In the middle of the creek, I stepped into one such mush, the ice, more fragile than I thought, broke beneath me and my body plunged into the water.
The present-day form of the watershed, with its broad sediment-filled valleys and deeply eroded side canyons, was shaped by a climate change during the previous Ice Age that produced Aliso Canyon, the creek's final gorge.
But spring creeks (streams formed by ice-cold springs) and rivers known as "tailwaters" (rivers fed by the dams that release cool water from the bottom) fish well all year round, even in the dog days of August.
