Sharing an excellent link regarding snake avoidance training, written by Janet Galante at Sit! Stay! Play! in Tucson, AZ.
In SoCal I do not do this with my dogs and we specifically avoid areas known to have rattlesnakes. That being said I know they can be found most anywhere on the Southern West Coast.
Please do your due diligence and feel free ask me if you have any questions/need more info on how to proceed.