Sorry, but I've never been there, however I thought many of our landscape photogs might be interested in this. The May 2007 issue of Sky and Telescope discusses the phenomenom of "moonbows" or rainbows caused by the moon's light, and provides dates and times when they would occur at the Lower Yosemite Falls in 2007. A considerable amount of effort went into the creation of the programme to predict dates and times (subject to local cloud cover) and it is an interesting article, including some examples with exposure times, and how to create one in your own back yard. Just an FYI for those that are interested. Maybe we'll see some examples?