Here is a report on a couple who got lost for a couple days in the desert. A day hike that turned into a near-death ordeal.

http://www.nydailynews.com/news/national/missing-reporter-rescued-nightmare-hike-article-1.1479604

Seems from other reports they had a couple granola bars, a couple water bottles and a canteen.

It was the classic recipe seen over and over.

1) inadequate gear

2) inadequate map

3) a series of miscalculations.

My major thought: When you are lost in the desert and find water (which another report states was in a grove of trees) don't abandon the two things in short supply -- water and shade.