The Whitewater River Run from Two Tenth Mile West and Downstream of Double Cabins Site to Confluence with Smoky Creek in California is approximately 4.5 miles long and has a class rating of III to IV. The ideal streamflow range for this run is between 300-800 cfs, which typically occurs during the late spring and early summer months.

There are several notable rapids and obstacles on this stretch of the river, including Upper and Lower Pucker Up, Death by Chocolate, and S-Turn. These rapids require expert maneuvering skills and knowledge of the river's flow, as they can be dangerous if not navigated correctly.

It is important to note that this section of the Whitewater River is closed to boating during the winter season from November 1 to April 30. Additionally, all boaters must wear a personal flotation device and carry a sound signaling device.

Overall, the Whitewater River Run from Two Tenth Mile West and Downstream of Double Cabins Site to Confluence with Smoky Creek is a challenging and exciting whitewater experience for experienced paddlers. It is important to respect the regulations and guidelines in place for the safety of all who enjoy this beautiful stretch of river.