This actually happened a few years ago right around Thanksgiving. A HUGE boulder let go from way up high on the canyon wall, punched right through the upper deck, bounced off the lower roadway and ended up in the Colorado River. The highway department got traffic flowing through the canyon again fairly quickly, but it took them a while to repair the road and get it fully operational. I think it's going to take a little more time this go round because I think the boulders destroyed both the upper and lower roadways.

I'll keep you up to date as things progress.