I'm semi-familar with the area (live 2 hours away, but used to travel near there for work occasionally). It would be pretty frigid even in a "cave." I believe GS was on the outskirts of the city, but this is a large metro area we're talking about, so while there are probably open fields between housing developments, I wouldn't expect there to be a lot of shelter type areas. And the altitude is around 6000-6500 ft above sea level, so the nights are going to be especially cold. I believe there may be some snow expected overnight tonight, and if even a slight breeze comes up, that wind chill will drop the temperature into the single digits or lower very fast. Without warm clothing, it wouldn't be a stretch to think someone would fall victim to the elements. However, I also think, barring the inability to go for help, an 11 year old would feel the very cold temperature, and walk into a business, or approach a person for help/warmth. I could see an older child trying to "rough it," but I feel (all my own opinion) GS is young enough to get afraid and cold.