Marin County Highpoint Trip Report

Mount Tamalpais (West Peak - 2,576 feet)

Date: Apr. 19, 2016
Author: Greg Slayden

I recently changed the Peakbagger.com listings for the summits of Mount Tamalpais so that the West Peak is now the Marin County high point and 2000-foot prominence peak, and the East Peak (tourist summit) is now just a sub-peak.

As part of this change, I have "grandfathered" in all current CA CoHP list completers who had not yet logged a West Peak ascent. I did this by creating a new kind of ascent, a "grandfather" ascent that is normally hidden except for list completion purposes. So the FRL and automated completion maps for current CA completers remain the same. Once a completer visits the West Peak, the "grandfather" ascent is then removed.

Incidentally, this research was initiated by the periodic review that is done to match up the peak databases of ListsOfJohn and Peakbagger so that the mobile app can log ascents at both sites at the same time. ListsOfJohn has always had the West Peak as the highest, although I suspect that quite a few people on LOJ have logged the West Peak as a CoHP thinking it was the East Peak.

As someone who now sees my CoHP and P2K counts drop by one, I feel the pain of those in the same boat. There is nothing I would like more for a conclusive survey to show that the much more attractive East Peak that I climbed long ago is higher.

But for me, I cannot ignore the principal evidence of the Marin County government's online GIS map. I have seen many of these maps from county planning/GIS departments, and there is a rough correlation between the affluence of the county and the quality of the mapping site. Marin is one of the wealthiest counties in the USA and their map is absolutely first rate. The difference of 4+ feet between the summits on that map is actually quite a bit, since I can think of other situations where a peak is awarded high point or prominence status by only 1 or 2 feet.

I normally don't trust handheld GPS readings too much, but Bob Burd's results are at least consistent with the map. I welcome any and all feedback from people in the area with sight levels, differential or handheld GPS, or other surveying equipment.

Reports are that if one hikes the fenceline around the West Peak military compound, one's head is above all of the man-made levelled platform inside the fence. This would appear to constitute an ascent under the "rules", I would hope. So hopefully this "new" high point is at least accessible.