Chaos Crags is the youngest group of lava dome

Lava dome

|250px|thumb|right|Image of the [[rhyolitic]] lava dome of [[Chaitén Volcano]] during its 2008–2009 eruption.In volcanology, a lava dome is a roughly circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano...

s in Lassen Volcanic National Park

Lassen Volcanic National Park

Lassen Volcanic National Park is a United States National Park in northeastern California. The dominant feature of the park is Lassen Peak; the largest plug dome volcano in the world and the southern-most volcano in the Cascade Range...

, California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

, having been formed as five dacite

Dacite

Dacite is an igneous, volcanic rock. It has an aphanitic to porphyritic texture and is intermediate in composition between andesite and rhyolite. The relative proportions of feldspars and quartz in dacite, and in many other volcanic rocks, are illustrated in the QAPF diagram...

 domes 1,100-1,000 years ago. The cluster of domes are located north of Lassen Peak

Lassen Peak

Lassen Peak is the southernmost active volcano in the Cascade Range. It is part of the Cascade Volcanic Arc which is an arc that stretches from northern California to southwestern British Columbia...

.

From the base of the crags and extending toward the northwest corner of the park is Chaos Jumbles, a cold rock avalanche which undermined Chaos Crags' northwest

Cardinal direction

The four cardinal directions or cardinal points are the directions of north, east, south, and west, commonly denoted by their initials: N, E, S, W. East and west are at right angles to north and south, with east being in the direction of rotation and west being directly opposite. Intermediate...

 slope 300 years ago. Riding on a cushion of compressed air

Compressed air

Compressed air is air which is kept under a certain pressure, usually greater than that of the atmosphere. In Europe, 10 percent of all electricity used by industry is used to produce compressed air, amounting to 80 terawatt hours consumption per year....

 (see air-layer lubrication), the rock debris traveled at about 100 mi/h, flattened the forest

Forest

A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...

 before it, and dam

Dam

A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

med Manzanita Creek, forming Manzanita Lake

Manzanita Lake

Manzanita Lake is a lake located in Lassen Volcanic National Park. Located near the park entrance, the lake is open for fishing and has rainbow, brown and brook trout....

.

In 1974 the United States Park Service took the advice of the USGS and closed the visitor center and accommodations at Manzanita Lake. The Survey stated that these building

Building

In architecture, construction, engineering, real estate development and technology the word building may refer to one of the following:...

s would be in the way of a rockslide from Chaos Crags if an earthquake

Earthquake

An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...

 or volcanic eruption occurred in the area.

Further reading

• CVO Description - Lassen Peak (Look under Lassen Volcanic National Park - Points of Interest for info on Chaos Crags in that site)