Mudslides: How Much Do We Really Know?

We hear about natural disasters such as  hurricanes, earthquakes, and tornadoes. One natural disaster we don’t often hear about are mudslides. The fatal mudslide that occurred near the small village of Oso, Washington claimed many lives, and searches are still in progress for missing people. Since this area has had slides over the last several years, one major question is could this catastrophe have been avoided?

ESL Voices Lesson Plan for this post  with Answer Key.

This aerial photo of the mudslide near Oso, Washington, was taken Saturday. National Geographic.

This aerial photo of the mudslide near Oso, Washington, was taken Saturday. National Geographic.

Excerpt: Mudslides Explained: Behind the Washington State Disaster Brian C. Howard,National Geographic

“On Saturday morning, a mudslide moved down the Stillaguamish River near the small former fishing village of Oso, Washington. Authorities have confirmed eight dead, eight injured, and as many as 108 people missing or unaccounted for as of Monday morning. The one-square-mile (2.6-square-kilometer) track of the mudslide also destroyed about 30 homes.

Jim O’Connor, a research hydrologist with the U.S. Geological Survey in Portland, Oregon, told National Geographic that the mudslide, which was up to 15 feet (4.5 meters) deep in some areas, was caused by ground made unstable by heavy rainfall.

A flag sticks out of a hole in a demolished home. Washingtonpost.com.

A flag sticks out of a hole in a demolished home. Washingtonpost.com.

This area has had slides in small increments over the last several years, but this took a huge bite of the hillslope this time, says O’Connor…A whole section of a hillside, about 700 feet [213 meters] high above the river, collapsed all at once,”says O’Connor. It’s amazing how much terrain it ended up covering.

What Is a Mudslide?

A mudslide, also called a debris flow, is a type of fast-moving landslide that follows a channel, such as a river. A landslide, in turn, is simply when rock, earth, or other debris moves down a slope.

How Mudslides Occur by Doug Smeath.News

How Mudslides Occur by Doug Smeath.News

Mudslides occur after water rapidly saturates the ground on a slope, such as during a heavy rainfall. According to O’Connor, it doesn’t take high relief in the topography to create a slide. Rather, it just takes a pull of gravity strong enough to bring down material that is made fluid enough by water.

How Are Mudslides Prevented?

Strategies to decrease the risk of mudslides include draining water off hillsides, armoring the bases of hills so they are not undercut by rivers, and loading the toe, says O’Connor.

This isn’t a situation where [the authorities] should have done something [to prevent it] because there is so much terrain there that this could have happened to, he says.

Mudslides- Torrential rain pushed tons of mud through villages in Brazil. Getty

Mudslides- Torrential rain pushed tons of mud through villages in Brazil. Getty

Searches continue for missing victims of mudslide.Photo-Washington Post.

Searches continue for missing victims of mudslide.Photo-Washington Post.

The CDC recommends that people exercise caution around steep slopes during rainfall. Immediate signs of a pending slide include tilting trees and sudden increases or decreases in rivers.” Read more…

American Red CrossVisit The American Red Cross to learn how you can help the families.

“OUR THOUGHTS AND PRAYERS GO OUT TO THE FAMILIES”-ESL VOICES-Flowers

ESL Voices Lesson Plan for this post

Level: Intermediate – Advanced

Language Skills: Reading, writing, speaking and listening. Vocabulary and grammar activities are included.

Time: Approximately 2 hours.

Materials: Student handouts (from this lesson) access to news article, and video.

Objective: Students will read and discuss the article with a focus on improving reading comprehension and learning new vocabulary. At the end of the lesson students will express their personal views on the topic of mudslides through group work and writing.

I. Pre-Reading Activities

Brainstorming

Directions: Place students in groups, ask students to think about what they already know about  the topic.  Next, have students look at the picture(s) in the text and generate ideas or words that may be connected to the article. Debrief as a class and list these ideas on the board. Students can use the UIE brainstorming chart.

Brainstorming chart by UIE copy

II. While Reading Activities

Vocabulary

Word Inference

Directions: Students are to infer the meanings of the words in bold taken from the article. They may use a dictionary, thesaurus, and Word Map  from  Education Oasis for assistance.

  1. A fatal mudslide occurred in rural northwestern Washington State over the weekend.
  2. Authorities have confirmed eight dead, and eight injured.
  3. The mudslide, which was up to 15 feet deep in some areas, was caused by ground made unstable by heavy rainfall.
  4. This area has had slides in small increments over the last several years.
  5. There been a lot of precipitation in the area over the past few months.
  6. The Stillaguamish River also has been eroding away the base of the hillside.
  7. A whole section of a hillside, high above the river, collapsed all at once.
  8. It ended up covering a huge amount of terrain.
  9. Strategies to decrease the risk of mudslides include draining water off hillsides.
  10.  Immediate signs of a pending slide include tilting trees and sudden increases or decreases in rivers.

Word Chart By Education Oasis

Word -Recognition 

Directions: Students are to circle or underline the correct word or phrases from the article. This exercise reinforces students’ attention on words that have been introduced in the reading. Have them skim the article to check  their responses.

  1. A fatal/fetal mudslide in Washington State points to the dangers of heavy rainfall.
  2. On Saturday mourning/morning, a mudslide moved down the Stillaguamish River.
  3. This area has had slides/sleds in small increments over the last several years,
  4. A mudslide is also called a debut/debris flow.
  5. It just takes a pulley/pull of gravity.
  6. Mudslides are also often triggered/tried by earthquakes
  7. Strategies to decease/decrease the risk of mudslides include draining water off hillsides.
  8. This isn’t a situation where the authorities should have done something to prevent/prevail it.
  9. The CDC recommends that people exercise caution around step/steep slopes during rainfall.
  10. Immediate sings/signs of a pending slide include tilting trees.

Reading Comprehension

True /False/NA-Statements

Directions: Review the following statements from the reading.  If  a statement is true they mark it T.  If the statement is  not applicable, they mark it NA. If the statement is false they  mark  it F and provide the correct answer.

  1. A fatal mudslide occurred in rural Washington  D.C. over the weekend.
  2. The missing people are mainly children.
  3. This is a situation where the authorities should have done something to prevent it.
  4. A mudslide is also called a debris flow.
  5. Mudslides occur after water rapidly saturates the ground on a slope, such as during a heavy rainfall.
  6. Mudslides tend to happen during dry seasons.
  7. In the United States, mudslides and landslides result in an average of 25 to 50 deaths a year.
  8. Strategies to decrease the risk of mudslides include draining water off hillsides.
  9. Immediate signs of a pending slide include tilting trees and sudden increases or decreases in rivers.
  10. Mudslides will occur in the future.

 Grammar Focus

Structure and Usage

Directions: The following groups of sentences are from the article. One of the sentences in each group contains a grammatical  error. Students are to identify the sentence (1, 2, or 3) from each group that contains the grammatical error.

I.

  1. 108 people missing or unaccounted for as of Monday morning.
  2. The mudslide also destroyed about 30 home.
  3. This area has had slides in small increments over the last several years.

II.

  1. A whole section of a hillside collapsed all at once.
  2. A mudslides is also called a debris flow.
  3. Mudslides tend to happen during wet seasons.

III.

  1. Mudslides are often triggered by earthquakes.
  2. Engineers put heavy mass, such as large rocks, at the base of a hill as prevention.
  3. The CDC recommend that people exercise caution around steep slopes during rainfall.

III. Post Reading Tasks

Reading Comprehension Check

WH-How Questions

Directions: Have students use the  WH-question format to discuss or to write the main points from the article.

Who or What is the article about?

Where does the action/event take place?

When does the action/event take place?

Why did the action/event occur?

How did the action/event occur?

Discussion/Writing Exercise

Directions: Place students in groups and have them answer the following questions. Afterwards, have the groups share their thoughts as a class. To reinforce the ideas, students can write an essay on one of the following discussion topics. Review Review ESL Voices Modes of Writing

  1. In your own words explain how mudslides occur.
  2. Why is it difficult for the search crew to find the missing people?
  3. The article states, “This area has had slides in small increments over the last several years, but this took a huge bite of the hillslope this time.”  Do you think there was a way the people could have been warned about this slide? Explain why or why not.
  4. Can mudslides be prevented in the future? How?
  5. Brazil has had several bad mudslides that have killed many people. Are there many mudslides in your country? Have you ever experienced a mudslide?

IV. Listening Activity   

Video ClipWashington Mudslide Kills at Least 14 Across A Mile

“A mudslide has killed 14 people and left 176 missing in Washington state after burying a mile-long stretch of land under 20 feet or more of mud. Rescuers are still searching the wreckage for survivors though they are holding out little hope for finding any signs of life. Mark Sovel and Jackie Koppell discuss whether or not this situation could have been avoided, in this clip from the Lip.”

 While Listening Activities

True /False/NA-Statements

Directions: Review the statements with students before the watching the video. As students listen to the video if a statement is true they mark it T. If the statement is  not applicable, they mark it NA. If the statement is false they mark it F and provide the correct answer.

  1. At the time of this broadcast, there were 25 houses and families destroyed.
  2. The wall of dirt that came down was a mile and a half wide.
  3. There had never been a previous slide in this area.
  4. The term “clear cut” means all vegetation is cut down to the earth.
  5. Some contributing factors to the mudslide were heavy rainfall and the number of people living in the area.
  6. The mudslide was compared to a tornado.
  7. Ways to prevent future mudslides were discussed.
  8. The speakers felt that this disaster received a lot of news coverage.
  9. This slide has been having trouble for the past 20 years.
  10. From the video you can guess that geologists are people who study the earth’s structure.

Post-Listening Activities

Questions for Discussion
Directions:Place students in groups and have them discuss the following questions.
1. After listening to this video have you learned any new information about mudslides?
2. Did you agree with everything the speakers said? Discuss which comments you agreed with and which ones you tended not to agree with. Explain why.
3. With your group members, make up questions that you would like to ask the speakers, geologists, or people who have survived mudslides in the past.

ANSWER KEY: Mudslides

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