Pilot Butte is a lava dome that was created from an extinct volcano located in Bend, Oregon. It is a cinder cone butte which rises nearly above the surrounding plains. Bend is one of six cities in the United States to have a volcano within its boundaries. The other examples are Mount Tabor in Portland, Oregon, Jackson Volcano in Jackson, Mississippi, Diamond Head in Honolulu, Glassford Hill in Prescott Valley and Pilot Knob in Austin, Texas.
The Pilot Butte State Scenic Viewpoint, presented as a gift to the State of Oregon in 1928, is a Bend icon. Pilot Butte itself is a popular hiking destination with two trails to the summit, each gaining about in elevation. There is also a trail around the base of the butte. A scenic road also winds up and around the cone. In 2018, the park was the most visited Oregon state park east of the Cascade Mountains. From the top, the entire city of Bend is visible, as well as several major Cascade peaks. Most prominent are the Three Sisters, Broken Top, and Mount Bachelor, which are located about to the west. The City of Bend launches Fourth of July fireworks from Pilot Butte each year.
Geography
Pilot Butte is located in Deschutes County, Oregon. It sits at the eastern edge of the city of Bend. The Geographic Names Information System database lists its summit elevation as ; the National Geodetic Survey lists its elevation as .
Geology
Pilot Butte is a Pleistocene cinder cone volcano. Its exact age is unknown. The volcanic rock has normal magnetic polarity, suggesting that it was laid down after the most recent geomagnetic reversal about 780,000 years ago. The butte's light-colored soil contains some ash from the eruption of Mount Mazama (which formed Crater Lake).
During the late Pleistocene, eruptions at Newberry Volcano produced voluminous basalt lava flows that extended into the area now occupied by Bend and Redmond. About 78,000 years ago, similar eruptive activity formed lava flows that surrounded Pilot Butte and filled the Deschutes riverbed, altering the course of the river by redirecting it to form a new channel to the west. The interior of these lava flows can be explored at Lava River Cave.
Lava deposited by Pilot Butte has an escarpment of more than . Pleistocene activity produced highly porphyritic lava with 10 to 15 percent plagioclase phenocrysts reaching diameters of up to . The lava is composed of 53.5 percent silica and 20 percent aluminum oxide. The volcano's lower southwest flank is covered with white, rhyolitic tephra, which is similar in composition to tephra found at Tumalo Creek; Sherrod et al. (2004) attribute the Tumalo Creek pumice to Pilot Butte. The pumice deposit at Tumalo Creek has a thickness of at least with lapilli reaching up to in length. White lapilli have phenocrysts of plagioclase and clinopyroxene ranging from . Darker lapilli are mostly aphyric.
Pilot Butte is extinct, not having erupted for several hundred thousand years.
Ecology
The most common tree on Pilot Butte is Western juniper, which is sometimes parasitized by witches' broom mistletoe. Also abundant are sagebrush and the similar plants bitterbrush and rabbitbrush. The invasive species cheatgrass is likely the most common grass on the butte. Wildflowers that appear include sand lily, rock cress, penstemon, paintbrush, buckwheat, yarrow, blazing star, mariposa lily, lupine, and monkeyflower. Ponderosa pine and red currant can also be found. Birds and deer feed on some of the plants, and some animals use snags as shelter.
History
Pilot Butte has been a landmark in the Bend area for many years, including for the Farewell Bend Park campground for travelers crossing the Deschutes River. It was also historically known as Red Butte, though this name is no longer used. The property encompassing the lava dome and its summit park were donated to the state of Oregon by F. R. Welles, Kempster B. Miller, and Charles A. Brown in memory of their business associate Terrence Hardinton Foley in September of 1928. Foley was the leader of the local Elks lodge until his death in a 1926 automobile accident, and the summit park has a memorial tablet dedicated to him.
Pilot Butte was named in 1851 by Thomas Clark, leader of the first party of European settlers to camp on the future site of Bend. The Clark wagon train approached the area from the east after recovering from the Clark massacre.