Friday, June 8, 2012

Mount Tamalpais

Yesterday I took advantage of my window of opportunity to ride my bicycle up Mount Tamalpais.

View Mount Tamalpais in a larger map

I started by driving to a little parking lot just on the north side of the Golden Gate Bridge, at the end of Alexander Avenue. I'm completely unfamiliar with the area, so followed the route recently described by Bill Bushnell, which appeared to be comprehensive. It would take me all the way around the mountain, offering lots of different experiences and a reasonable distance, for me.

San Francisco Bay, from Sausalito. Angel Island
on the left, Alcatraz in the middle, San Francisco toward the right

I got started a little after 10 AM, on a clear and cool day. Alexander Avenue crosses under the highway and then becomes the main drag through Sausalito, after changing names several times. It was here I found that I had not properly calibrated by altimeter, since it was reading 70 feet below sea level on Bridgeway Road. I suspect it was reading 100 feet too low.

A seminary in San Anselmo, on the
"wrong" Bolinas Ave.
Just as northbound Bridgway gets consumed by the highway, a bike path appears to carry you through the marshes at the top of the bay. After a modest number of wrong turns, I managed to Camino Alto, which climbs over a hill into the town of Corte Madera. These towns up here all seem to have really well-defined downtown areas, and after Camino Alto turned into Magnolia, it passed pleasantly through downtown Corte Madera.

A little farther north I got to Bolinas Avenue, a little earlier than expected, and turned to ride up the mountain. But this was the wrong Bolinas, it turns out, so I returned to San Anselmo Avenue and continued north. A couple of miles and one town further north, I got the right Bolinas and headed west.

Bolinas starts the real climbing, reaching 1000 feet after a climb of about 3 miles, with an average gradient of about 5.5%. It climbs along a steep ridge with lots of houses. The houses have little decks on which to park cars, then stairs down to the houses below. Bolinas climbs past a county club, tops a ridge, then descends through thick woods toward Alpine Lake, about 400 feet lower.

Alpine Lake
The dam at Alpine Lake
Alpine Lake is a stunningly pretty reservoir surrounded by thick woods. On this Thursday I had the whole thing to myself, or nearly so. I took this opportunity to eat a little pseudo-food and contemplate just how lucky I am.

The climb away from the lake is perhaps the prettiest part of this ride, climbing up switchbacks on a heavily wooded ridge. It reminded me of the upper part of Black Road. While it seemed steep at the time, it appears to average a grade of only 5.9%. The most difficult KM of the day was in this section, with an average grade of 8%.

A switchback on Bolinas, climbing up from Alpine Lake
Bolinas Road meets Ridgecrest Boulevard at about 1500 feet. Ridgecrest is level for a bit, and then climbs out of the woods and starts running along a grassy ridgeline, climbing to the 2000 foot level and then leveling off again. The views from Ridgecrest are spectacular. Toward the west is the Pacific, toward the east are the mountains, and a little further along Ridgecrest, you get postcard views of San Francisco.

Looking west from Ridgecrest. Bolinas is in the lower-right.
At the intersection with Pan Toll Road, Ridgecrest begins a climb to the peaks. The climb to the west peak takes you up to about 2500 feet, with a grade of 6.7%. In compensation, you get lovely views of San Francisco and the bay.

The east peak of Tamalpais, with Mount Diablo in the
background. Toward the right, Angel Island and San Francisco
There's a saddle between the west and east peaks that has some of the steepest ramps I saw on the day. While the east peak is higher, as far as I can tell the road is actually much lower. I think to get to similar elevation you have to take one of the many trails. I got my fill of the views and refilled my water, then headed back down. Well, first up to the west peak, then down.

I took the steep Pan Toll Road down to the Panoramic Highway, then dropped through a series of residential roads into Mill Valley. This must be the more popular route up Mount Tamalpais, because I passed dozens of riders coming the other way. At the end of Miller Road I got back on the bike trail, and reversed my steps back to the parking area.

Mist blowing past the Golden Gate Bridge
By this time it was the late afternoon, and the west side of the Golden Gate Bridge was open to bikes. There were so few bikes that I doubted my luck, thinking it must be a mistake. The wind on the bridge was fierce, blowing in some mist. When I stopped to take some pictures, the wind blew over my bike and threatened to blow the camera out of my hand. Nonetheless, the views were great, and the lack of traffic was an unusual treat.

I returned to the car and began the long trip home, now firmly in rush hour traffic. It was well worth it.

Elevation profile. This appears to be about 100 feet low.
This ride was almost 55 miles, with 4300 feet of climbing. Had I planned the climb myself, I'm sure I would have taken the shortest route, and missed the lovely Alpine Lake. Perhaps next time I can the same thing in reverse, or maybe a route incorporating Stinson Beach.

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