Of at least four glaciers that John Muir recorded in Yosemite during the 1860s–70s, only one still qualifies as a glacier. These dwindling bodies of ice, cradled in tracks of the vast glaciers that sculpted Yosemite’s canyons and domes over the past 2–3 million years, are shrinking largely due to global climate change. While few visitors to Yosemite ever lay eyes on a glacier, each year hundreds of thousands of sightseers and hikers visit ecosystems fed by their meltwater. Glacial runoff differs from snowmelt in one important way: it continues through late summer and fall after the snow disappears, sustaining life in high-elevation ecosystems that would otherwise be dry. During spring, the trickle of glacial meltwater barely registers in the thundering, snowmelt-fed Lyell Fork of the Tuolumne River. However, by September and October in dry years, that same steady glacial runoff can make up 90% of the river’s smaller flow. This reliable water source shapes ecosystems and human recreation in Lyell Canyon, Tuolumne Meadows, and the Grand Canyon of the Tuolumne River.
[{"glaciers": "n/a", "shrinking": "n/a", "heights": "n/a"}]
[{"glaciers": "n/a", "shrinking": "yes", "heights": "n/a"}] [{"glaciers": "n/a", "shrinking": "n/a", "heights": "n/a"}]