Opuntia polyacantha

Opuntia polyacantha is a variable species that occurs on a large territory, from California to Rocky mountains in Colorado and Wyoming. It is a species of frost hardy plants and it's presents usually indicates that at least some winter frost happens in the area. in California  this species was reported as high as almost 14000 ft./4000m in White Mountains.
Plants from different places display different spines, often white but also brown like in the picture, and also straight, curled, or hair-like. Flowers can be yellow, like in all the plants I've seen East of Las Vegas, or pink.
This picture is taken near town of Page in Arizona. This is the land of red Navajo sandstone, that forms the background of the picture.
In culture this plant presents no problem, and due to it's cold hardiness it is recommended for outdoor cactus garden in the areas with snowy winters. If grown in the pots they require large containers, to accommodate the plant size. There are also relatively small forms of that species.