This Joshua Tree search and rescue team tries to head off calamity before it strikes

It's 4 p.m. in Joshua Tree National Park and the air temperature is hovering around 99 degrees -- relatively mild for an August afternoon. But at ground level, the sand along the popular Hidden Valley Nature Trail has reached a scorching 136. "I don't want my bare feet on that," says ranger Anna Marini as she shows her thermometer gun reading to a couple visiting from Switzerland, who are appropriately awed. Marini uses the tool as a prop to engage hikers traversing this surreal desert wilderness that's roughly the size of Rhode Island. As the coordinator of the park's Preventative Search and Rescue Program, her mission is to protect visitors from hazards that include extreme heat, razor-sharp cacti and thirsty bees.