When a Utah Driver is driving in the complete opposite lane of an exit or a turn they need. Because they're Utards, they realize at the last second that they need to get to the other side of the road and instantly weave across multiple lanes of traffic without ever looking and almost causing fatal crashes. If they're on a freeway, sometimes they barely miss the crash barrels as they exit off the freeway.
"OH SH**! That Utard almost caused me to crash when they Utah Weave'd across the 4 lanes of the freeway!"