The Rainbow area is located just west of the Donner areas and is listed in the Northern California Bouldering guidebook. If you have a chance make sure to visit this place. The guidebook does not do this zone justice.
I was skeptical of the quality not only because the problems are all unnamed, but because most are ungraded as well. To my surprise the granite climbed extremely well consisting of independent lines, varying movement, and interesting holds. Not only do these problems deserve both numbers and names, but stars as well.
Rainbow is the only place I have wanted to return since I have been exploring Northern California. If you are climbing during the summer make sure to wait until the late afternoon, as the boulders get a lot of sun.
I managed to climb what was listed in the guidebook as a "huge dyno, V?" however after discovering two key crimps I found a fluid static sequence to a thuggish top out that shredded my stomach. This problem felt roughly V8, and is too good to remain nameless so I dubbed it Ground Beef, V8.
Here are a few photos of the climb along with a video of a very fun, crimpy V4 (also nameless) that has been dubbed "Muffin Stuffer."
Recovering from the end battle.
Photos by Liberty Herring