OK, I admit my ignorance...are all Arizona/southwest sunsets like this? I spent a week or so traveling through Grand Canyon, Phoenix, Tucson, and every evening was a spectacular play of color that lasted quite a while after the actual sunset. The show continued when we drove through Blyth, CA, and a few days later in my own Central Valley of California, and our valley is not known for colorful sunsets.
So, is this usual? The last time I saw sunsets like these, Pinatubo volcano in the Philippines had pumped cubic miles of ash and aerosols into the stratosphere, and the sky lit up like fireworks. Then again, I spend a lot of time indoors ignoring the sky, and so maybe I have just been missing out. In any case, I appreciated the spectacle!