| Bannock Mountain | |
| Elevation Ft: | 7769 |
| Elevation Ref: | [1] |
| Prominence Ft: | 640. |
| Prominence Ref: | [2] |
| Isolation Mi: | 2.98 |
| Parent Peak: | Plummer Mountain (7,870 ft) |
| Etymology: | Bannock |
| Map: | Washington#USA |
| Mapframe: | yes |
| Mapframe-Zoom: | 8 |
| Mapframe-Caption: | Interactive map of Bannock Mountain |
| Country: | United States |
| State: | Washington |
| Region: | Snohomish / Chelan |
| Region Type: | County |
| Part Type: | Protected area |
| Part: | Glacier Peak Wilderness |
| Range: | Cascade Range North Cascades |
| Coordinates: | 48.2558°N -120.9921°W |
| Topo: | USGS Agnes Mountain |
| Rock: | Metamorphic Gneiss[3] |
| Age: | Cretaceous |
| First Ascent: | 1936 |
Bannock Mountain is a 7769feet summit in the North Cascades of Washington state.
Bannock Mountain is located 28miles east of Darrington, Washington, in the heart of the Glacier Peak Wilderness, on land managed by Mount Baker–Snoqualmie National Forest and Okanogan–Wenatchee National Forest. The mountain is situated on the crest of the Cascade Range, along the common border shared by Snohomish County and Chelan County. Precipitation runoff from the mountain's east slope drains to the Stehekin River via Agnes Creek, whereas the west slope drains into Sulphur Creek and the south slope into Canyon Creek, which are both tributaries of the Suiattle River. Topographic relief is significant as the summit rises 3770abbr=offNaNabbr=off above Sulphur Creek in 1.5miles and 2370abbr=offNaNabbr=off above Bannock Lakes in one-half mile (0.8 km). The first ascent of the summit was made on July 28, 1936, by Hermann Ulrichs, Art Johnson, and Dwight Watson. The mountain's toponym has been officially adopted by the United States Board on Geographic Names,[1] and refers to bannock, which is a variety of flatbread or quick bread that early surveyors prepared over campfires.
Subduction and tectonic activity in the area began during the late cretaceous period, about . The area was previously an oceanic environment, consisting mainly of sedimentary and volcanic rocks.[4] Extensive volcanic activity began to take place in the oligocene, about .[5] However, mountain building in the area did not begin until the miocene, approximately .[4] Bannock Mountain is located in the Cloudy Pass batholith, an intrusive formation that was formed approximately, during the early miocene.[4] [6] Glacier Peak, a stratovolcano that is 11miles south of Bannock Mountain, began forming in the mid-Pleistocene.[4] Due to Glacier Peak's proximity to Bannock Mountain, volcanic ash is quite common in the area.
Throughout the ice age, the North Cascades were mostly covered in thick glaciers, extending to near Puget Sound. Glaciation was most prevalent approximately, and most valleys were ice-free by .[4] As a result, valleys in the area are deep and u-shaped, and mountains tend to be rocky, with steep slopes and narrow summits.
Bannock Mountain is located in the marine west coast climate zone of western North America.[4] Most weather fronts originating in the Pacific Ocean travel northeast toward the Cascade Mountains. As fronts approach the North Cascades, they are forced upward by the peaks (orographic lift), causing them to drop their moisture in the form of rain or snowfall onto the Cascades. As a result, the west side of the North Cascades experiences high precipitation, especially during the winter months in the form of snowfall.[4] Because of maritime influence, snow tends to be wet and heavy, resulting in high avalanche danger.[4] 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.[4] Due to its temperate climate and proximity to the Pacific Ocean, areas west of the Cascade Crest very rarely experience temperatures below 0°F or above 80°F.[4] The months of July through September offer the most favorable weather for viewing or climbing this peak.