Urban slang for "impressive."
When someone or something does something impressive, it is "gulch." It's like a verbal fist bump. A compliment often said about someone or something from humble origins. Also said sarcastically between two people from modest origins.
Gen X alum of Blossom Gulch (an elementary school in Oregon that schooled many of humble origins), began calling things "gulch" on Facebook as a nod to their origins and whatever was impressive now. Others soon followed.
Dude, that was gulch. Your truck is gulch.