This is a light blue Pendleton wool blanket with stripes. I spotted something similar online and it was listed as the Olympic National Park Series blanket but it seems to be difficult to find any info about that, so not sure at all. It has a white Pendleton label, which is also unusual.

Size is about 76 x 61 inches. It has slight shrinkage, one small stain (in the photo of a yellow stripe), a few spots of edge unraveling, slight age-related wear.