F A C T S H E E T Federal Emergency Management Agency LANDSLIDES AND MUDFLOWS Landslides and mudflows usually strike without warning. The force of rocks, soil, or other debris moving down a slope can devastate anything in its path. Take the following steps to be ready. Get a ground assessment of Learn to recognize the landslide Make evacuation plans. your property. warning signs. Plan at least two evacuation Your county geologist or county ■ Doors or windows stick or jam routes since roads may become planning department may have for the first time. blocked or closed. specific information on areas ■ New cracks appear in plaster, vulnerable to landsliding. Consult tile, brick, or foundations. Develop an emergency a professional geotechnical expert communication plan. for opinions and advice on ■ Outside walls, walks, or stairs landslide problems and on correc- begin pulling away from the In case family members are tive measures you can take. building. separated from one another during a landslide or mudflow ■ Slowly developing, widening (this is a real possibility during Minimize home hazards. cracks appear on the ground or on the day when adults are at work ■ Plant ground cover on slopes paved areas such as streets or and children are at school), have a and build retaining walls. driveways. plan for getting back together. ■ ■ In mudflow areas, build chan- Underground utility lines break. Ask an out-of-state relative or nels or deflection walls to direct ■ Bulging ground appears at the friend to serve as the “family the flow around buildings. base of a slope. contact.” After a disaster, it’s often easier to call long distance. ■ Remember: If you build walls ■ Water breaks through the Make sure everyone knows the to divert debris flows and the flow ground surface in new locations. name, address, and phone number lands on a neighbor’s property, ■ Fences, retaining walls, utility of the contact person. you may be liable for damages. poles, or trees tilt or move. ■ You hear a faint rumbling sound that increases in volume as the Insurance landslide nears. Mudflow is covered by flood ■ The ground slopes downward in insurance policies from the National one specific direction and may Flood Insurance Program. Flood begin shifting in that direction insurance can be purchased through under your feet. a local insurance agency. If inside a building: Stay away from the slide area. Check the building foundation, ■ Stay inside. There may be danger of addi- chimney, and surrounding land tional slides. for damage. ■ Take cover under a desk, table, or other piece of sturdy furniture. Check for injured and trapped Replant damaged ground as persons near the slide area. soon as possible since erosion If outdoors: Give first aid if trained. caused by loss of ground cover ■ Try to get out of the path of can lead to flash flooding. the landslide or mudflow. Remember to help your neigh- ■ Run to the nearest high ground bors who may require special Seek the advice of a geo- in a direction away from the path. assistance — infants, elderly technical expert for evaluating landslide hazards or designing ■ If rocks and other debris are people, and people with corrective techniques to reduce approaching, run for the nearest disabilities. landslide risk. shelter such as a group of trees or a building. Listen to a battery-operated ■ If escape is not possible, curl radio or television for the Mitigation into a tight ball and protect your latest emergency information. head. Mitigation includes any activities that Remember that flooding may prevent an emergency, reduce the chance occur after a mudflow or a of an emergency happening, or lessen Sinkholes landslide. the damaging effects of unavoidable emergencies. Investing in preventive A sinkhole occurs when groundwater mitigation steps now, such as planting Check for damaged utility lines. dissolves a vulnerable land surface such ground cover (low growing plants) on as limestone, causing the land surface to Report any damage to the utility slopes, or installing flexible pipe fiting to collapse from a lack of support. In June company. avoid gas or water leaks, will help reduce 1993, a 100-foot wide, 25-foot deep the impact of landslides and mudflows sinkhole formed under a hotel parking in the future. For more information on lot in Atlanta, killing two people and mitigation, contact your local emergency engulfing numerous cars. management office. EMERGENCY PUBLIC INFORMATION September 1993 BACKGROUNDER LANDSLIDES AND MUDFLOWS WHAT IS A LANDSLIDE? Landslides occur when masses of EMERGENCY INFORMATION rock, earth, or debris move down a 1. Acres of property may be damaged and buildings and slope. Landslides may be very small homes destroyed by landslides. Landslides can provoke associ- or very large, and can move at slow ated dangers such as broken electrical, water, gas, and sewage to very high speeds. Many land- lines, and disrupted roadways and railways. slides have been occurring over the 2. Landslide warning signs include cracks opening on same terrain since prehistoric times. hillslopes, evidence of slow, downhill movement of rock and They are activated by storms and soil; tilting of trees, poles, or walls; or visible changes such as fires and by human modification of the formation of sags and bumps in the slope. the land. New landslides occur as a 3. Landslide, mudflow, and debris-flow problems are often result of rainstorms, earthquakes, caused by land mismanagement. Improper land-use practices on volcanic eruptions, and various ground of questionable stability, particularly in mountain, canyon, human activities. and coastal regions, can create and accelerate serious landslide problems. Land-use zoning in partnership with professional WHAT IS A MUDFLOW? inspections and proper design can alleviate many problems Mudflows (or debris flows) are associated with landslides, mudflows, and debris flows. rivers of rock, earth, and other debris saturated with water. They develop when water rapidly accu- mulates in the ground, such as during heavy rainfall or rapid snowmelt, changing the earth into a flowing river of mud or “slurry.” A slurry can flow rapidly down slopes or through channels, and can strike with little or no warning at ava- lanche speeds. A slurry can travel several miles from its source, growing in size as it picks up trees, Landslides occur in every state of the union and its island territories. California, West Virginia, cars, and other materials along the Utah, Kentucky, Tennessee, Puerto Rico, Ohio, and Washington have the most severe landslide way. problem. HELP YOUR COMMUNITY GET READY HOW THE PUBLIC CAN HELP The media can raise awareness about landslides and mudflows by providing AFTER A DISASTER important information to the community. Here are some suggestions: When disaster strikes, people 1. In an area prone to landslides, publish a special section everywhere want to help with emergency informaton on landslides and mudflows. those in need. To ensure that Localize the information by including the phone numbers of this compassion and gener- local emergency services offices, the American Red Cross, osity are put to good use, the and hospitals. media can highlight these 2. Report on what city and county governments are doing to facts: reduce the possibility of landslides. Interview local officials Financial aid is an immediate need of about local land-use zoning regulations. disaster victims. Financial contributions 3. Interview local officials and major insurers regarding the National Flood should be made through a recognized Insurance Program. Remind your community that mudflow is covered by voluntary organization to help ensure flood insurance policies from the National Flood Insurance Program. that contributions are put to their intended use. 4. Work with local emergency services and American Red Cross officials to prepare special reports for people with mobility Before donating food or clothing, wait impairments on what to do if an evacuation is ordered. for instructions from local officials. Immediately after a disaster, relief workers usually don’t have the time or facilities to setup distribution channels, DID YOU KNOW... and too often these items go to waste. ■ The most expensive landslide in ■ The Loma Prieta earthquake in Volunteers should go through a U.S. history occurred in Thistle, October 1989 triggered thou- recognized voluntary agency such as the Utah, in spring, 1983. It sands of landslides throughout American Red Cross or Salvation Army. reached 1 1/2 miles from top to an area of 5,400 square miles. They know what is needed and are bottom and ranged in width In addition to causing at least prepared to deal with the need. Local emergency services officials also from 1,000 feet to about 1 mile. tens of millions of dollars of coordinate volunteer efforts for helping Total costs attributable to the damage to houses, other struc- in disasters. landslide exceeded $500 mil- tures, and utilities, landslides Organizations and community groups lion. blocked many transportation wishing to donate items should first routes, greatly hampering rescue contact local officials, the American Red ■ Landsliding in the United States and relief efforts. Cross, or Salvation Army to find out is estimated to cause an annual what is needed and where to send it. loss of about $1.5 billion and at ■ Mudflows tend to flow in Be prepared to deliver the items to one least 25 fatalities. channels, but will often spread place, tell officials when you’ll be there, out over a floodplain. They and provide for transportation, driver, generally occur in places where and unloading. they have occurred before. EMERGENCY PUBLIC INFORMATION September 1993.