| The Dome | |
| Elevation Ft: | 5720 |
| Prominence Ft: | 400 |
| Isolation Mi: | 1.16 |
| Isolation Ref: | [1] |
| Parent Peak: | Mount Margaret (5,860 ft) |
| Location: | Mount St. Helens National Volcanic Monument Skamania County, Washington, U.S. |
| Range: | Cascade Range |
| Map: | Washington#USA |
| Map Size: | 270 |
| Label Position: | right |
| Coordinates: | 46.3083°N -122.1581°W |
| Volcanic Arc: | Cascade Volcanic Arc |
| Topo: | USGS Spirit Lake West |
| Rock: | Tertiary volcanic rock |
The Dome is a 5720feet mountain summit located in Mount St. Helens National Volcanic Monument, in the Gifford Pinchot National Forest, in Skamania County of southwest Washington state.[2] It is situated in the Cascade Range, less than 2miles north of Spirit Lake, and 1.28miles northeast of Coldwater Peak. Its nearest higher neighbor is Mount Margaret, 1.16miles to the northeast, and Mount St. Helens rises 7.5miles to the south. Precipitation runoff from The Dome is drained by Coldwater Creek, a tributary of the North Fork Toutle River.
The history of the formation of the Cascade Mountains dates back millions of years ago to the late Eocene Epoch.[3] Geological events occurring many years ago created the diverse topography and drastic elevation changes over the Cascade Range leading to various climate differences. During the Pleistocene period dating back over two million years ago, glaciation advancing and retreating repeatedly scoured and shaped the landscape.[3] With the North American Plate overriding the Pacific Plate, episodes of volcanic igneous activity occurred.[3] The lateral blast from the 1980 eruption of Mount St. Helens was pointed straight toward The Dome and stripped the vegetation from the slopes. Due to Mount Saint Helens' proximity to The Dome, volcanic ash is common in the area.[4]
The Dome is located in the marine west coast climate zone of western North America.[4] Most weather fronts originate in the Pacific Ocean, and travel northeast toward the Cascade Mountains. As fronts approach, they are forced upward by the peaks of the Cascade Range (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 Cascades experiences high precipitation, especially during the winter months in the form of snowfall. 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. The months July through September offer the most favorable weather for viewing or climbing this peak.