It’s that time of year again to guess when the Tioga Road will open!
The 2023 Tioga Road opening date prediction is July 8th,
with a 50% chance that the real opening date will fall between June 30th and July 17th.
This is based off of the WHOPPING 62.5″ of snow water equivalent measured at the Tuolumne Meadows snow course for the April 1 report.
This huge winter has presented many challenges, this prediction included. For the first time since I started this in 2018 I need to extrapolate, to make a prediction outside of the range of existing data. I’ve ditched the linear model, since it doesn’t make sense that added inches of Apr 1 snow will have the same effect on road openings from May to July. As a snowpack lingers into June, those extra inches will melt away much faster than they did in April and May. So, I switched to a Gompertz function that has a lower and upper asymptote, which seems like a much better model for how snowpack affects getting a road open.
Snow data here: https://cdec.water.ca.gov/reportapp/javareports?name=COURSES
Past Tioga Road opening dates here: https://www.nps.gov/yose/planyourvisit/seasonal.htm
Data excluded from the model are the grey dots and dates on graph: 1995 and earlier, due to significantly different wilderness and safety regulations; 2020-2022 due to covid impacts to Park staffing and operations.
I’ll post the R code to Github if anyone wants it.