Tioga Pass and Glacier Point Roads Opening Dates 2013

Post date: Apr 04, 2013 3:43:32 AM

The April 1 CA snow surveys are complete. Now it's time to talk about road openings in Yosemite National Park. Check last year's blog for specifics about my estimation methods. There has been some talk about Yosemite's plowing effort being impacted by the Government Sequestration. To me, this doesn't seem like it should be possible for Yosemite. In 2012 nearly 4 million people visited the park. Assuming an average of 2.5 people per vehicle ($20/vehicle), ~$32 million was earned via entrance fees alone. Include merchandise, food/beverages, and campground expenditures and they probably have a few more million in the bank. Yosemite's operating budget in 2011 (when attendance was slightly higher than 2012) was $29 million. That's an at least $3 million surplus. Why would Yosemite allow the cut in government spending to affect its snow plowing, when that would directly affect how many visitors come to the park over the summer tourist season and therefore how much money they bring in? If the road is cleared of snow for a longer period of time, more people will drive over it to the park from the east. If it is not cleared, they won't come to the park (some may drive around, but not all). That doesn't add up to me, but neither does the sequestration. Therefore, I'm not going to consider it in my estimations for the opening dates. The April 1 snow surveys are reporting a snowpack at 53% in the Merced River Basin (47% this time last year) and 52% in the Tuolumne River Basin (43% last year). These numbers are not that different from last year but the snow is not spread as well between elevations as it was last year. Around 70% of the snowpack is above 8,000'. That means that the lower elevations will melt off more quickly, but a majority of the snowpack will take longer to melt (assuming colder temperatures at higher elevations). Last year I estimated (with April 15 data) the Glacier Point Road would open between April 27 and May 5. It opened April 20. I should have stuck with my gut feeling and estimated April 20-27, but no plowing reports had been posted on the NPS page when I posted the estimate (April 18) so I conservatively went for a later date. Last year I estimated (with April 15 data) the Tioga Pass Road would open between May 4 and 12. It opened May 7. Based on last year's snowpack and opening dates, I'm assuming that the two roads will open slightly (~1-2 weeks) later this year. Based on the Tenaya Lake (TNY) April 1 snow-water-equivalent (SWE) data, the Glacier Point Road will open sometime near May 8 and the Tioga Pass Road will open near May 14. Assuming the maximum SWE value has already occurred, the Glacier Point Road will open sometime near May 7 and the Tioga Pass Road will open near May 15 based on the TNY Max SWE data. The estimated dates from the three sites (Tenaya Lake, Dana Meadows, and Virginia Lakes Ridge) for the two roads are all very close to each other. Therefore, based on these numbers and last year's opening dates, I estimate that the Glacier Point Road will open sometime between April 29 and May 7. I estimate that the Tioga Pass Road will open sometime between May 10 and 18. As with every year, this will depend on how much more precipitation the Sierra in Yosemite gets and how warm/cold the temperatures are between now and these estimates. I should probably move the Glacier Point Road opening date a little earlier because of the concentration of the snowpack above 8,000', but for now I'll stick with what the data estimate. If these predictions prove accurate, it will definitely be an early opening for both roads, however that means that the Yosemite waterfalls will quickly dissipate. Thus, if you want to see the waterfalls during decent flows, plan on arriving at least two weeks earlier than an average year. The peak flow for the Merced River at the Pohono Bridge (which can serve as a proxy for the nearby creeks) on average occurs on May 27 (probably nearer to early- to mid-May for this year). Similar to last summer, don't expect Yosemite Creek to be running into August but we can look forward to the Glacier Point and Tioga Pass Roads being open for longer than usual (unless winter arrives early). Check back in a couple of weeks when I update this post with April 15 numbers (more accurate than April 1 and Max SWE numbers).

UPDATE (4/16):

The April 15 estimates are looking pretty consistent with the April 1 estimates. The little bit of snow the Sierra received yesterday and today shouldn't affect these estimates too much. The TNY April 15 data is estimating a May 12 opening date for the Tioga Pass Road and May 6 for the Glacier Point Road. Both of these estimates are two days earlier than the April 1 estimates. Therefore, I'm going to slightly move the Tioga Pass Road estimate earlier but leave the Glacier Point Road estimate. The updated estimates are between April 29 and May 7 for the Glacier Point Road and between May 9 and 17 for the Tioga Pass Road.