Sierra Mountain Guides GUESTS! You must provide proof of COVID-19 vaccination prior to the start of your program, OR provide a current negative COVID test result taken within 48 hours of the start of your program. This policy applies to our guides as well. Failure to provide this information before the start of your program will result in program cancelation without a refund. Before your program please send your proof of vaccination or proof of a negative COVID test to firstname.lastname@example.org with your name and program in the subject line.