Earliest Mono Pass Opening Since 1987 Published by Yosemite Chalet On May 12, 2014 The Tioga Pass opened on 2 May 2014, the earliest since 1987. Backcountry hikes are opened up earlier than ever; and, you can count on very few mosquitos compared to most years. Get into the Yosemite Backcountry early in 2014 Categories:Blog, June Lake Tags:June Lake snow conditions, Tioga Pass opening