Contra Costa County High Point Trip Report

Mt. Diablo (3849 ft)

Date: June 16, 1998
Author: Andy Martin

Tuesday June 16th was a day of "rest", while Dinesh Desai expertly guided us through a Bay area county tour, letting Dinesh's Acura do most of the climbing. The view from Mount Diablo in Contra Costa county encompasses one of the greatest areas on the planet (per Dinesh), and Mt. Shasta and the Sierra Nevada mountains are visible on a clear day. It also has a mighty impressive benchmark at the HP, where the CA survey base and meridian lines cross.

Comment from Adam Helman - It is a widely held misconception that Mt.Diablo has a tremendous viewshed. This misconception arose from the ability to view both the High Sierra and Mt.Shasta simultaneously, with the erroneous assumption that everything in-between is also visible. Simple trigonometry disproves this assumption - the only reason these distant landmarks are visible is because of their considerable altitude. Virtually all the land closer in is not theoretically visible from the summit of Mt. Diablo.

Edward Earl has performed somewhat exact calculations of the theoretical viewshed for different peaks, including some for which the visible areas are considerably greater than Mt.Diablo, e.g. Mauna Kea and Denali. Please lay to rest the absurd claims made of Mt.Diablo's viewshed.