A person driving through Yellowstone National Park at night saw something extraordinary and, thankfully, he managed to capture it and share it with all of us. The video was filmed very recently, on December 21, 2020.
In their own words, "The Wapiti lake wolf pack is made up of 20 wolves. At last light I witnessed 7 wolves chase a cow elk across the road and eventually kill the elk 50 yards off the road. This occurred in the northern range of Yellowstone national park."
The Wapiti pack (and Wapiti means elk, by the way) was formed in 2014 by the wolf designated 755M, a former alpha of the Lamar pack, after a couple of years of wandering throughout the area, during which time it did not find a mate or join any other packs. Now the Wapiti pack is thought to be the largest in the Park.
Seeing the wolves near the roads is relatively rare, and seeing them in pursuit of prey while crossing the road is even moreso. They are sometimes photographed farther from the roads, in the backcountry, where they often spar with grizzlies over their kills. But with most grizzlies presumably hibernating, they ought to be able to enjoy their feast of elk in peace.