Prickly pear cacti, genus Opuntia, are easily-recognized members of the cactus family (Cactaceae) with a very wide native range across the Americas. There are more than 150 species, native from southern Canada to Argentina and Chile. They are also called nopales (singular nopal).
It is fall in the Rockies. The aspen leaves are turning colors. As I write this in early October, Trail Ridge Road at the top of Rocky Mountain National Park is closed due to snow. It should reopen, but, clearly, it is winter now at 11,000 feet. Where I live, at 5,000 feet, we have not yet had a frost. As cold temperatures move down the mountains, aspen and other deciduous trees will change color and then lose their leaves at successively lower elevations. Lots of opportunity to enjoy the spectacle.