Subscribe for 17¢ / day

CODY, Wyo. — Yellowstone National Park officials have asked 2017 visitors to adopt their "Safe Selfie" policy.

Park officials issued the policy in response to a rash of irresponsible and illegal behavior during the past two years.

Yellowstone broke records by topping 4 million tourists for the first time in 2015 and then topped that with 4.2 million visitors last year. Mixed in the millions, a number of visitors have made bad decisions.

Two summers ago, five people taking selfies provoked bison into attacking them. No one was killed, but medical treatment was needed.

Last year, a tourist died after walking off a pedestrian boardwalk into a thermal area.

The Yellowstone East Gate will open at 8 a.m. Friday.