I grew up near Yellowstone and know they change trails all the time for that reason. The underground “plumbing” undergoes constant changes due to daily small earthquakes and movement of the strata. Active geysers go dormant and dormant ones suddenly come back to life. The Earth is a living entity and life on top of geologic hot spots like Yellowstone can be very unpredictable!
I last visited Yellowstone back in 1991. It is surely one of the most beautiful places on earth. The sulfur smell in some places, though, would gag a maggot.
Interesting how the lake is tilted over ( bubble from below ) killing the forest of large trees.