California, Yosemite National Park. On 26 September while descending a boulder field with a slope of approximately 45°, Gary Leonard (25) stepped out onto a large boulder about the size of a dining room table. It tipped forward, causing him to jump down the slope. He jumped and ran about 30 feet before he realized that it was hopeless to try to stay under control. He tucked and rolled and slammed into the boulders, trying to protect his head as much as possible.

Source: Gary Leonard.

Analysis: Assuming that the boulder tipping was unavoidable, the only things that could have lessened his injuries would have been heavier boots (he was wearing rock shoes), long pants instead of shorts, and he should have been wearing his hard hat instead of carrying it.