They say it is because of the dust and dirt in the atmosphere that causes the sunsets to be so brilliant.
The refraction of the light hits the particles and bounces back the brilliant reds, oranges and yellows that can be seen in this sunset. The upper atmosphere was windy as you can see from the distortion of the clouds. The layer of darker purple was a darker area of the coming storm. We were getting ready to have a winter snow storm. Boy, did we get a snow storm!