This hike is on unofficial trails or no trail at all in Ignacio Valley Open Space Preserve. Thunderbird Ridge is a subridge that starts at Thunderbird Court off of Fairway Drive in Novato, and rises up to Big Rock Ridge fire road at about 1400 feet. This hike starts out hugging the side of the ridge until we climb up to its spine and meet the unofficial Thunderbird Ridge Trail. We take this trail up the ridge until we meet the Pensacola Creek Trail, which drops a short distance down to Pensacola Creek, which is dry except during the rainy season. There the trail ends and we take the creek bed all the way down to Pensacola Court, then circle back up to the starting trailhead to conclude the hike. There is a series of 6 waterfalls on this creek during the rainy season.