I almost tripped over this snake this morning in my front yard and would like help identifying it.

I live in northern Arizona at about 6200' elevation. This snake is quite large. I would guess 5' at least. He wasn't aggressive and didn't move when I was pretty close.

Here is a photo of him:
https://goo.gl/photos/AQGyu3hfKtVdAL5X7

Thanks in advance.

Marc