Levels of a pathogen than can destroy brain cells and lead to death have been found in thermal features in Grand Teton National Park in Wyoming, leading park officials to urge visitors to avoid Huckleberry Hot Springs, Polecat Springs, and Kelly Warm Spring.

A teenager who apparently ran away from a service detail on Thursday was found Saturday morning in Grand Teton National Park and taken to a Jackson, Wyoming, hospital for a welfare check before being handed over to the Teton County Sheriff's Department, park officials said.

The most unnerving moment of my climb to the summit of Grand Teton in its namesake national park in Wyoming came on the way down via the Owen-Spalding Route. We had come to the point where you have a free rappel of about 100-120 feet, and after the guide tied me into the rappel line and checked my harness and rappel device, I took a step back toward the brink of the cliff, only to have him shout, "Wait, wait," and then proceed to retie the gear.

Nearly four decades have passed since Congress directed the National Park Service to establish visitor carrying capacities for the National Park System, yet few parks have done so, according to a review by Public Employees for Environmental Responsibility.