Hillman Peak is an

summit A summit is a point on a surface that is higher in elevation than all points immediately adjacent to it. The topographic terms acme, apex, peak (mountain peak), and zenith are synonymous. The term (mountain top) is generally used only for ...

on the west rim of

Crater Lake Crater Lake ( Klamath: ) is a volcanic crater lake in south-central Oregon in the Western United States. It is the main feature of Crater Lake National Park and is a tourist attraction for its deep blue color and water clarity. T ...

Crater Lake National Park Crater Lake National Park is a national park of the United States located in southern Oregon. Established in 1902, Crater Lake is the fifth-oldest national park in the United States and the only national park in Oregon. The park encompasses t ...

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

. It is the highest peak on the caldera rim and ranks as the second-highest peak in the park. It is situated 1.5 mile northwest of Wizard Island.

Topographic relief Terrain (), alternatively relief or topographical relief, is the dimension and shape of a given surface of land. In physical geography, terrain is the lay of the land. This is usually expressed in terms of the elevation, slope, and orientati ...

is significant as the summit rises 1,973 feet above the lake in 0.57 mile. Rim Drive traverses the western slope of the peak. Precipitation runoff from the peak's east slope drains into Crater Lake whereas the west slope drains to the Rogue River via Copeland Creek.

History

Hillman Peak was named by William Gladstone Steel for John Wesley Hillman (1832–1915), a prospector who discovered Crater Lake on June 12, 1853. The peak's "Hillman Peak" toponym was officially adopted in 1928 by the

United States Board on Geographic Names The United States Board on Geographic Names (BGN) is a Federal government of the United States, federal body operating under the United States Secretary of the Interior. The purpose of the board is to establish and maintain uniform usage of geogr ...

. Variant names prior to 1928 included Glacier Peak and Maxwell Peak.

Climate

Based on the

Köppen climate classification The Köppen climate classification divides Earth climates into five main climate groups, with each group being divided based on patterns of seasonal precipitation and temperature. The five main groups are ''A'' (tropical), ''B'' (arid), ''C'' (te ...

, Hillman Peak has a

subalpine climate The subarctic climate (also called subpolar climate, or boreal climate) is a continental climate with long, cold (often very cold) winters, and short, warm to cool summers. It is found on large landmasses, often away from the moderating effects of ...

. Most

weather front A weather front is a boundary separating air masses for which several characteristics differ, such as air density, wind, temperature, and humidity. Disturbed and unstable weather due to these differences often arises along the boundary. For ins ...

s originate in the Pacific Ocean, and travel east toward the Cascades where they are forced upward by the range (

Orographic lift Orographic lift occurs when an air mass is forced from a low elevation to a higher elevation as it moves over rising terrain. As the air mass gains altitude it quickly cools down adiabatically, which can raise the relative humidity to 100% and cr ...

), causing them to drop their moisture in the form of rain or snowfall. As a result, the Cascades experience high precipitation, especially during the winter months in the form of snowfall. Winter temperatures can drop below with wind chill factors below . In the Crater Lake area, winter lasts eight months with an average snowfall of 41 feet (12.5 m) per year. Rim Drive is only open during the summer due to the heavy snowfall as the road is covered by more than of snow with drifts as deep as in some areas."Facts and Figures"
National Park Service, United States Department of Interior, Crater Lake, Oregon, November 2001. During winter months, weather is usually cloudy, but due to high pressure systems over the Pacific Ocean that intensify during summer months, there is often little or no cloud cover during the summer.

Geology

Hillman Peak was created when

Mount Mazama Mount Mazama ( Klamath: ''Tum-sum-ne'') is a complex volcano in the western U.S. state of Oregon, in a segment of the Cascade Volcanic Arc and Cascade Range. The volcano is in Klamath County, in the southern Cascades, north of the Oregon– ...

, a large

stratovolcano A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with ...

erupted violently approximately 7,700 years ago and formed on the

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the str ...

rim. The peak is the remnant of a parasitic cone on the western flank of

, such that when the caldera formed, the eastern half of the Hillman cone disappeared. The peak is composed of lava flows containing pyroxene and hornblende

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomina ...

s and

breccia Breccia ( , ; ) is a rock composed of large angular broken fragments of minerals or Rock (geology), rocks cementation (geology), cemented together by a fine-grained matrix (geology), matrix. The word has its origins in the Italian language ...

s. Evidence suggests that the pre-eruption Hillman cone acted as a

cleaver A cleaver is a large knife that varies in its shape but usually resembles a rectangular-bladed tomahawk. It is largely used as a kitchen knife, kitchen or butcher knife and is mostly intended for splitting up large pieces of soft bones and slas ...

which was never entirely covered by glacial ice.Ann G. Harris, Esther Tuttle, Sherwood D. Tuttle (2004), ''Geology of National Parks'', Volume 1, Kendall/Hunt Publishing Company, , p. 536. According to the Global Volcanism Program (GVP), Hillman Peak is classified as a subfeature stratovolcano of Mount Mazama.

Gallery

File:Hillman Peak, Crater Lake Caldera.jpg File:Hillman Peak, Crater Lake.jpg File:Hillman Peak.jpg File:Crater Lake, Hillman Peak and The Watchman.jpg, Hillman Peak (center) and The Watchman (left)

References

External links