Ever read a winter route description and felt like you'd been handed a bill in a foreign language? Grade III, Grade IV, Grade V, then a little number after it that nobody explains. Scottish winter grades look like a code, and honestly, they kind of are. Once you crack the logic, though, the whole thing clicks. Here's what separates Grade I from Grade IV terrain, what those numbers are really telling you, and why the grade on paper doesn't always match the day you're actually