Yosemite squirrel plague and falling tree limbs shut down parts of park

The usually happy height of the summer season at California's bustling and beloved Yosemite National Park took a dark turn when a fallen tree branch killed two young campers and a campground closure was announced because of the presence of plague.

The large limb from a black oak fell on the tent of the two young campers as they slept in the heart of the park Friday, Yosemite spokesman Scott Gediman said.

The campers, described only as under 18, were both dead when rangers arrived at the crowded Upper Pines Campground in response to 911 calls, Gediman said.

What led to the limb falling, and its exact size, were not immediately revealed.

Large fallen limbs are a common occurrence at Yosemite, and they have occasionally led to deaths. The most recent was in 2012, when a park concession employee died when his tent cabin was hit. Two tourists were killed and nine were injured in 1985 when a 25-foot branch fell onto an open-air tram.

Meanwhile on Friday, park officials said they will temporarily close another popular campsite after two squirrels died of plague in the area.

Tuolumne Meadows Campground will close from noon Monday through noon Friday so authorities can treat the area with a flea-killing insecticide. Campers had their reservations canceled at the 304-site campground so the insecticide can be sprayed into rodent "burrow holes," the California Department of Health said Friday.

"Although this is a rare disease, and the current risk to humans is low, eliminating the fleas is the best way to protect the public from the disease," said Dr. Karen Smith, director of the state Health Department.

A child was diagnosed with the plague after camping with his family at Yosemite's Crane Flat Campground in mid-July. The park reopened Crane Flat on Friday after treating that campground for four days with an insecticide.

The child has been recovering in a hospital. No other family members became sick.

The last three cases of human plague in the state occurred in 2005 and 2006, the Health Department said. All three of those patients survived.

Since 1970, 42 people in California have contracted plague, resulting in nine deaths. Health officials find plague-infected animals every year, mostly in the state's mountains and foothill regions.

Meanwhile, in another popular national park, Yellowstone, a hiker was killed by a grizzly bear earlier this month. 

A grizzly bear was euthanized Thursday after an autopsy of a hiker confirmed that the bear killed him in Yellowstone National Park, CNN reported.

Lance Crosby died as a result of traumatic injuries sustained from a grizzly bear attack, park officials said. Additional evidence also pointed to the female bear as his attacker, they said.

"As managers of Yellowstone National Park, we balance the preservation of park resources with public safety," said Yellowstone National Park Superintendent Dan Wenk. "Our decision takes into account the facts of the case, the goals of the bear management program and the long-term viability of the grizzly bear population as a whole, rather than an individual bear."

Two twin female cubs captured with her will be transferred to the Toledo Zoo sometime this fall, the zoo announced Friday.