Logs and branches were stuck in the trees and brush ten feet or more above the rim of the gorge. There was a 15 inch diameter ponderosa pine stuck in the canyon wall about 50 feet up that hadn't been there the year before. Clearly, conditions change frequently and dramatically. After entering the canyon, you'll encounter several obstacles right away. These are all fairly simple to down climb, unless there are pools.
Water makes footing treacherous.
In most cases, you'll be taking advantage of rocks and logs jammed or placed below boulders to lower yourself, usually only 6 to 10 feet. If there are pools, you'll be unable to assess the depth, and unable to see the logs and rocks for footing. If you find the water too cold or are uncomfortable proceeding here, abandon the hike here. There are sure to be worse obstacles ahead. If there are no pools, then you've lucked out, and passage will be much simpler.