Ramble downhill through a wonderland of ferns and old-growth redwoods. Huge old trunks tower over your head, and beams of sunlight filter down along with birdsong and the sweet smell of the branches. This is the Steep Ravine trail, and it’s aptly named. The ravine that it follows is steep, with towering canyon walls rising up on both sides from a narrow boulder-strewn creek below. In places, giant redwoods have fallen and wedged between the banks, like rustic bridges or a giant game of pick-up sticks. The trail itself is also steep, dropping precipitously down the flanks of Mt. Tam. A little over half-way from the Pantoll Parking Lot, there’s a sturdy 10-foot wooden ladder to help hikers down a particularly steep spot.
The uphill leg of the loop is a chunk of the Dipsea trail, which Steep Ravine merges in to after nearly two miles. At this junction you can either keep heading downhill to Stinson Beach, or you can turn left to head up the Dipsea (I like to do the loop hike in this direction since this part of the Dipsea has a LOT of steep stairs, which can get slippery when it’s wet. But in any weather I’d rather go up these stairs than down them).
The Dipsea leg is as beautiful as the Steep Ravine leg – the first section of the climb is so steep that it feels like you’re in a tree fort. The crowns of big old Doug firs are at eye level when you look out over the canyon. Later in the hike you pass through huckleberry stands, dense groves of skinny (young?) redwoods, gnarled oaks and bays, and then out into the high Tamalpais grassland with sweeping views of the Pacific ocean. The trail heads south for a ways before meeting up with the Coastal Fire Road that leads you back to Pantoll.
This loop is a great spot to see a lot of different kinds of plants. The microclimate changes sharply as you move up and down the mountain, from the narrow moist ravine into the open high-elevation grassland. There are many species of shade-loving ferns and lots of wildflowers. At this time of year, a lot of plants were in fruit but I still saw lots of blooms as well.
If you’re coming from Stinson Beach, you can also start this hike at the bottom end of the loop instead of at Pantoll. Park in the large turnout near a metal access gate, right before the big metal “Mt. Tamalpais State Park” sign. Then you can head uphill on the Dipsea for half a mile, until you come to the Steep Ravine junction. Veer left across a aged wooden footbridge to do the uphill leg of the loop on the Dipsea.