Yellowstone National Park has enacted several emergency fire measures in the midst of fire season. Effective immediately, these restrictions are aimed to protect Yellowstone as well as guests.
The new restrictions are as follows: no campfires, either charcoal or wood fire, in the backcountry. This includes fires made in existing fire rings. No smoking unless there is absolutely no flammable material in any direction or at least three feet (read: you have to be on a boat or up to your waist in water). Smoking is acceptable if immediately next to the fire ring in certain designated campsites.
If not in the backcountry, smoking is acceptable if: you're in an enclosed vehicle, a dwelling, picnic area or in a cleared area. It should go without saying, but just in case: don't throw your cigarette butts out the window for the love of God.
Campfires are not prohibited in designated camping areas and developed areas, but as always, please make sure that your campfires are fully out before leaving them unattended.
Remember the words of a wise bear: only you can prevent forest fires.