Maybe, if there's a layer of leaves, it's slick & rotten & nasty after all the snow starts melting? But still doesn't that dry up? making a natural mulch? I'll have to research this.
After conferring with my local expert I learn that it's necessary to rake the leaves 'cause patchwork grass (read: laid sod, coastal, stay-green-so-the-neighborhood-looks-pretty) does NOT grow here naturally. So, to keep it alive--although dormant--'til next year, it must be raked.