Jagged peaks rise above Cascade Canyon, where powerful Pleistocene glaciers carved the canyon and sculpted the range. From the shores of Jenny Lake, the landscape passes through forest communities, wetlands along Cascade Creek, high meadows filled with wildflowers, and rocky windswept slopes of the alpine community. Both forks of Cascade Canyon once held glaciers: Schoolroom Glacier clings to a cliff at the head of the south fork, and Lake Solitude fills a glacial cirque at the head of the north fork. Alpine conditions are harsh, with a brief summer that brings splashes of colorful wildflowers against bare rock, while winter brings deep snow, sub-zero temperatures, and winds gusting to more than 100 miles per hour. Many animals migrate or hibernate during winter, but pikas gather grass in summer and store it as haystacks under rocks for winter forage, while yellow-bellied marmots hibernate up to nine months of the year. Small, dense mounds of cushion plants grow slowly between rocky outcrops, storing nutrients for years before blooming.