I didn't even know this place existed. I do own a mountain bike, however my mountain bike skills are at the beginner level. Nowhere near the expert/trick level required at the Colonnade. I have done a faceplant already on my mountain bike when I first started mountain biking years ago. The Park looks awesome, however it'll be some time, till I get to the other trails, for now I'll stick to the beginner trails. I still love the warning sign, and I don't have pictures of it, it says something like this: "Full Face Helmet and Body Armor highly recommended."
It was fun to watch the mountain bikers do tricks and jumps on some of the trails. This area under I-5, many years ago were filled with squatters and junkies. Now it's replaced with mountain bikers and the area truly cleaned up. Since the whole colonnade is a community resource, it's quite amazing how such space has been transformed to an urban park.