I'm pretty sure the comment you're replying to didn't intend to suggest any connection between the Sierra Nevada and the Great Smoky Mountains, but to show that the usage of "smoky" as an adjective for mountains does not necessarily mean literal smoke. The Great Smoky Mountains are just one example of this usage (thus "Great".) Similarly note the usage of "blue peaks" which probably doesn't mean the peaks were actually blue but that Rayleigh scattering was being observed.