Grasshopper Glacier

Grasshopper Glacier lies in a north-facing cirque at about 11,000 feet on Iceberg Peak, in the Absaroka-Beartooth Wilderness north-east of Cooke City. It became famous for the insects frozen in its ice: swarms of the Rocky Mountain locust, Melanoplus spretus, a species that has since gone extinct. Radiocarbon dating puts their burial in the 1300s. The first recorded report came from J.P. Kimball, a mining geologist with the US Geological Survey, who described "thousands of tons" of grasshoppers in the ice. In 1914 Forest Service officials sent specimens to the US Bureau of Entomology.

Know before you go that the glacier the old guidebooks describe has gone. Glacier researchers measured its area at 0.42 square kilometres in 1966, 0.26 in 1994 and 0.05 in 2005, when it ceased to be an active glacier. By 2015 the largest piece left was about 0.025 square kilometres, with no crevasses, and the ice no longer reached the lake below it. Descriptions of a glacier a mile long and half a mile wide are long out of date, and you are unlikely to see grasshoppers in the ice today. Two other ice fields in the Beartooths share the name, so make sure maps and directions are for the one above Cooke City.

Getting there is a serious trip. About 2 miles east of Cooke City, near Colter Campground, turn north off US-212 onto the Lulu Pass–Goose Lake Road (Forest Road 6493). It is extremely rough and suitable only for high-clearance four-wheel-drive vehicles, and it is open only in the dry weeks of late July and August. The road ends at the wilderness boundary, where bikes and all other mechanised travel are banned. From there it is about 4 miles on foot past the upper end of Goose Lake to the saddle between Sawtooth Mountain and Iceberg Peak. Allow a full day. A snowfield near the saddle is often mistaken for the glacier.

There is no fee. This is grizzly country, so carry bear spray, and set off early because afternoon thunderstorms are common at this height. For current road and trail conditions, call the Beartooth Ranger District in Red Lodge on 406-446-2103.