In mid to late summer fireweed begins blooming in the middle of the stalk, with each successive flower blooming just above the one before it. As the last flowers are blooming at the top of the stalk, the earliest blooms seed and turn to cotton, as seen below. When the fireweed turns to cotton, Alaskans say there are about six weeks until winter begins. I took this video sometime ago and it sure seems to be right. Jaspers mountains got snow last night!
Fireweed Turns to Cotton In Fall