Blind Descent by Nevada Barr

As a park ranger, Anna Pigeon has been in some pretty tight spots, beginning with Track of the Cat, but thus far she's managed to stay out of claustrophobia-inducing caverns. Now a friend and colleague has been injured in Lechuguilla caverns and is asking for Anna. “A chilling image filled Anna's mind: herself crouched and whimpering, fear pouring like poison through her limbs, shutting down her brain as the cave closed in around her.”

But when Anna finally reaches her friend's side, Frieda murmurs “It wasn't an accident.” A cave is just another kind of locked room for a mystery plot, so if someone tried to kill Frieda, that person must be one of the small group she was with. There are tensions and undercurrents between various members of the team, but none that seem to be directed toward Frieda.

Blind Descent immerses the reader in its beautiful and deadly environment, and in the techniques and camaraderie of caving enthusiasts. But we see them through Anna's fear-clouded eyes as she puzzles out why someone would want to get rid of Frieda and whether she's next. Nevada Barr's other novels about Anna Pigeon are equally evocative of their varied park settings.

Dana Cameron's series features archaeologist Emma Fielding, another strong woman with an outdoor profession, who also has to confront terrifying mysteries. Or if caving excites you, try the other BlindDescent: the Quest to Discover the Deepest Place on Earth, nonfiction by James M. Tabor.