West Butte is a mountain summit located in Toole County, Montana, United States.
West Butte is the highest peak in the Sweet Grass Hills and the highest in the county. It is situated north-northeast of Shelby, Montana, and south of the CanadaâÂÂUnited States border, on land administered by the Bureau of Land Management. Precipitation runoff from the mountain drains south to the Marias River and north to the Milk River. Topographic relief is significant as the summit rises above the surrounding plains in which makes it a prominent landmark visible for many miles.
West Butte is an exposed laccolith composed of diorite porphyry and monzonite which was created by an igneous intrusion through older Mississippian sedimentary rocks during the Eocene, about 50 million years ago. These sedimentary rocks are primarily limestone and shale. Over time, erosion of the sedimentary rock has exposed the solidified laccolith which is more resistant to weathering.
The Sweet Grass Hills, which are centered in buffalo hunting territory, are sacred to the Blackfoot and other tribes. The Blackfoot called West Butte "ami sÃÂtse katúyis" which means "west side sweet pine." In 1806, Meriwether Lewis sighted West Butte from the Missouri River, which is distant, and George Mercer Dawson reported seeing it from away at Blackfoot Crossing in Alberta. The landform's toponym has been officially adopted by the United States Board on Geographic Names.
Based on the Köppen climate classification, West Butte is located in a semi-arid climate zone with long, cold, dry winters and hot summers with cool nights. Winter temperatures can drop below âÂÂ10 ðF with wind chill factors below âÂÂ30 ðF. The wettest period of the year is generally May through August, with up to 20 inches of precipitation falling annually on the peak.
West Butte peak has a dry winter subarctic climate (Köppen Dwc).
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