These notes will help you fill out your Cispus Journal
(Click here for 2007 picts)

Use the following for pages 14 to 22:
Answers for Blowing, Flowing, Glowing

Answers for Constructive Destruction

Answers for Survivor Johnston Ridge

Ponds Hike Picts (to check your sketches, pgs 24 & 25)

Use the info here to complete p. 13 in your Cispus Journal.

On May 18, 1980 Mt Saint Helens erupted. Since Mt Saint Helens erupts with cinders and lava flows it is a composite volcano. The blast went sideways so it was a lateral blast. Mt Saint Helens is one of the several Cascade Range volcanoes.On May 18 an enormous column of ash thrust 15 miles into the sky. It continued to eject ash for about nine hours. The plume deposited ash and pumice downwind from the volcano. The ash was blown eastward by the wind at about 60 miles per hour. Some of the ash reached the eastern United States within 3 days. Small particles entered the jet stream and circled the Earth within two weeks.

There are many examples of life returning to Mt Saint Helens from the trees and plants that are all over the blast zone. Also in Meta Lake there are many trees as well as tadpoles, birds and fish. Deer are spotted at times, too.

Mt St Helens’ Mud Flows - As the ash column rose, the edges collapsed onto the slopes of the newly formed crater. This superheated ash quickly melted and mixed with existing snow and ice. Then it began to flow downslope. The water quickly picked up rock debris as it sped from the volcano. This debris included boulders as large as 20 feet in diameter. Mudflows can travel as fast as 30 miles an hour. They can easily rip trees, houses, and bridges from the ground. Mudflows sped from the volcano's west, south, and east sides within minutes of the eruption. The largest mudflow started on the debris-avalanche deposit about 4 hours later. Most of the water that poured across the surface of the debris avalanche deposit came from the deposit itself. This included water that had been trapped inside the volcano, and melting blocks of ice that had been glaciers on the volcano. The mudflow sloshed from side-to-side as it rushed through forests and clearcuts. It left its unmistakable mark on the land. From the toe of the deposit, millions of tons of debris broke loose and devastated downstream communities. Homes were carried away and deposited many miles downstream, or simply, destroyed by bridges. The mighty Columbia River was closed to freighter traffic for several days as the debris was dredged out.

Mt St Helens’ Lava Dome - Inside the giant horseshoe- shaped crater of Mount St. Helens, 17 eruptions between 1980 and 1991 have built a mound-shaped pile of lava called a lava dome. The dome is 3,450 feet wide and contains about 97 million cubic yards of lava. At its highest point from the crater floor, it is more than 1300 feet tall. That's taller than the Empire State Building. But as large as this may seem, the dome has only replaced about 4 percent of the volcano that was removed on May 18, 1980. Each new eruption adds lava to the dome. This was usually as an oval-shaped lava flow as thick as 100 feet and more than 1,000 feet across. Mt Saint Helens erupted again in 1986, then again in October of 2004. It has been erupting since 2004 and continues to erupt even now.

Spirit Lake - The debris avalanche that triggered the eruption slid north into Spirit Lake and west 25 kilometers down the North Fork Toutle River valley, covering the valley floor with unconsolidated debris to an average depth of 45 meters and as much as 180 meters in some places. The debris avalanche raised the level of Spirit Lake 64 meters and dammed its natural outlet even higher. Many small ponds filled closed depressions on top of the avalanche deposit, and several lakes formed in tributaries dammed by the avalanche.