Early Christmas at Yellowstone National Park after surprise wintry blast.
13 Sep 2016 – Four to eight inches of snow were forecast through Monday night with further snowfall expected early Tuesday as temperatures dropped to 32F (0C).
This is not the first time the park has been hit by a freak snowstorm. In 2014 snow swept across the park at the end of August.
Thanks to Craig Adkins for this link