What's the origin of using "toboggan" to mean a knit cap?

I'd always know the word "toboggan" to mean a sled. In the last couple years I've met people who insisted on calling their winter knit caps "toboggans." All of these people happened to be from either Kentucky or Tennessee. Wikipedia mentions that

In the United States south and midwest, especially Appalachia, it is often called a "toboggan".

but there's no info about origin. When and where did this usage come from?

Solution 1:

Etymonline.com lists this shift in the late 20's, probably because it's the type of cap you would wear while tobagganing. I imagine it was probably first called a "toboggan cap", and then eventually the "cap" was just dropped.

Solution 2:

Chris's intuition is confirmed by the OED, which lists "toboggan-cap" among similar compound formations as "toboggan-bag" and "toboggan-chute".