Part 3 in a 3-Part Series about Severe Weather
Weather-related disasters lead to devastating loss of life and cost billions of dollars each year. The first post in our three-part series about severe weather disasters focused on extreme heat. The second entry discussed floods. This last post will tackle landslides and mudslides, since they so often accompany other severe-weather events. My son, JR, likes slides at the park but these slides don’t sound like fun.
Landslides & Mudslides
Landslides occur when masses of rock, earth, or debris move down a slope. Debris flows, also known as mudslides, are a common type of fast-moving landslide that tends to flow in channels.Landslides are caused by disturbances in the natural stability of a slope. They can accompany heavy rains or follow droughts, earthquakes, or volcanic eruptions.
The term “landslide” refers to a wide range of ground movement, such as rock falls, deep failure of slopes, and shallow debris flows. An over-steepened slope combined with gravity could lead to landslides. These situations further contribute to landslide risk:
- Erosion by rivers, glaciers, or ocean waves, which create super steep slopes
- Rock and soil slopes that have been weakened by snowmelt or heavy-rain saturation
- Earthquakes that stress weak slopes
- An out-of-control laundry pile (Just kidding.)
Mudslides develop when water rapidly accumulates in the ground, leading to a surge of water-saturated rock, earth, and debris. Mudslides usually start on steep slopes and can be activated by natural disasters. Areas where wildfires, earthquakes or human modification of the land have destroyed vegetation on slopes are particularly vulnerable to landslides during and after heavy rains. Damage can be substantial because debris flows often contain mud, rocks and other corrosive materials. I’ve seen videos where dogs get caught up in mud. Scary stuff.
Slide-Related Health Threats
Landslides and debris flows result in 25 to 50 deaths each year in the United States. The health hazards associated with landslides and mudflows include:
- Rapidly moving water and debris that can trap people and lead to trauma;
- Broken electrical, water, gas, and sewage lines that can result in injury or illness; and
- Disrupted roadways and railways that can endanger motorists and disrupt transport and access to health care.
- Roadblocks which prevent grocery trucks from delivering bacon to local markets.
How to Be Safe Before Intense Storms Hit
- Assume that steep slopes and areas burned by wildfires are vulnerable to landslides and debris flows.
- Learn whether landslides or debris flows have occurred previously in your area.
- Contact local authorities about emergency and evacuation plans.
- Develop emergency and evacuation plans for your family, business and building occupants.
- Create an emergency communication plan.
- Stock up on pork chops and chew toys.
How to Be Safe During Intense Storms and Rainfall
- Listen to the radio or watch TV for warnings from local officials.
- Be aware of sudden increases or decreases in water level in streams and creeks, which might indicate debris flow upstream.
- Look for tilted trees, telephone poles, fences, or walls, and for new holes or bare spots on hillsides.
- Listen for rumbling sounds that might indicate an approaching landslide or mudflow. My pals and I like to bark when we hear this kind of thing. You’re welcome.
- Be alert when driving. Roads could become blocked or closed due to collapsed pavement or debris.
- If landslide or debris flow danger is imminent, quickly move away from the path of the slide.
How to Be Safe After a Landslide or Debris Flow
- Stay away from the site. Flooding or additional slides may occur after a landslide or mudflow.
- Check for injured or trapped people near the affected area, only if you can do so without entering the path of the landslide or mudflow.
- Listen to the radio or TV for emergency instructions after an event.
- Report broken utility lines to appropriate authorities.
- Consult a registered professional engineer with soils engineering expertise for advice about reducing additional landslide problems and risks.
- Try to resist the urge to take a mud bath. I know; it’s difficult.
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