Several states in Mexico are considered high-risk areas for potential mud or landslides. Being classified as high risk means the rainfall patterns, steep terrain slopes, reduced vegetation cover, poor soil quality and earthquake, hurricane, or volcanic activity combine to make the area dangerous.
Between 1925 and 2017, there were 1,967 recorded landslides throughout Mexico which resulted in at least 3,447 deaths. Most were caused by excessive rainfall in the areas. The majority were in central and southern Mexico, including the states of Hidalgo, Mexico, Puebla, Tlaxcala, and Veracruz.
- In 1920, a debris flow from the Rio Huitzilapan triggered by a 6.5 earthquake killed between 600 and 870 people in the village of Barranca Grande.
- October 1, 1976, a landslide in La Paz, Baja California claimed at least 1,000 lives after Hurricane Liza hit the area.
- October 7, 1999, more than 210 people were killed and tens of thousands forced to evacuate after weeks of torrential rains. In the town of Mixun which is about 100 miles northeast of Mexico City, as many as 40 people were buried in a landslide including 17 schoolchildren and their teacher. In the nearby town of Teziutlan, 26 people were killed after a hillside mudslide buried an entire neighborhood. More than 166 people were killed in the state of Puebla, 50 in Veracruz as well as numerous fatalities in Chiapas, Tabasco, and Hidalgo.
- In 2004, Hurricane Ivan caused underwater mudslides that destroyed an offshore oil rig in the Gulf of Mexico spilling 700 barrels of oil per day for 15 years.
- September 17, 2013, Hurricane Ingrid and Tropical Storm Manuel caused buildings to collapse in Veracruz killing at least 12 people and forcing more than 20,000 to evacuate.
- August 8, 2016, Hurricane Earl caused mudslides that buried homes in Huauchinango, Puebla killing 25, while mudslides in Veracruz caused the death of 11 more.
- July 10, 2019, a mudslide destroyed a home in Santo Tomas Chautla village, located near the city of Puebla. The family was celebrating a graduation. Three adults and four children were killed, while two other children were severely injured.
- September 28, 2019, Santa Maria de Tlahuitoltepec, Oaxaca 11 people went missing after a mudslide.
Landslides occur when masses of earth, rock or debris move down a slope. Debris flows and mudslides are flowing rivers of earth, rock, and debris. They develop during periods of intense rainfall or runoff, flow more rapidly than a person can run, and strike with little or no warning. They grow in size as they accumulate boulders, trees, and buildings and can travel miles. They don’t always stream directly down but can flow sideways as well.
Mudslides are more likely to happen in areas
- That they have happened before
- Where wildfires have destroyed vegetation
- At the bottom of slopes or canyons
- Where slopes have been altered by road and building construction
- Along streams and rivers
- Where there is a lot of surface runoff
There are a few things you can do to prevent being affected by mudslides. First, do not build your home near drainage ways, close to mountain edges, near steep slopes or in natural erosion valleys.
Be sure to learn about the history of your property. Have landslides happened there before? If they have, they are more likely to occur again. Huge boulders scattered randomly about can be leftover signs of past debris flows or landslides. Watch how the water runs off during storms, then make channels or deflection walls to redirect water run-off. Plant trees and plants on slopes to reduce soil erosion. Build retaining walls to restrain the soil along the slope.
Develop a family emergency response and evacuation plan that includes choosing a rendezvous location and a safety plan for any pets or livestock you may have.
If you live in an area that is considered at high risk for mudslides, pay special attention to the following warning signs indicating a land or mudslide is imminent:
- Saturated ground
- Unusual bulges in the pavement, sidewalk or ground
- Soil moving away from building foundations
- Cracking or concrete floors and foundations
- Doors and windows that stick indicating the frames have shifted
- Learning walls, trees or poles
- Sunken roads
- Rapidly increasing water levels that are full of sediment
- A sudden decrease in water levels even though it is raining
- Rumbling sounds
- Trees cracking or boulders hitting the ground
If you were unable to evacuate, move to a second floor or roof if possible. Do not try to outrun a mudslide downhill. Instead move laterally, attempting to get to higher ground. If you are driving or walking, do not try to cross flooded streams. Watch out for rocks that may have already fallen, collapsed pavements and bridge damage.
After a landslide, stay away from the area. Additional movement may occur. Be alert for flooding which often occurs after a mudslide or debris flow. Check for trapped or injured people near the slide location without entering the slide path. Be careful of downed electrical lines.
Once the area has been declared safe, check your home’s foundation for damage. Replant the affected area as soon as possible. Seriously consider relocating since the chances of mudslides happening at the same location are very high.
Mudslides are just on of the unpredictiable and deadly natural disasters that occur frequently in Mexico. Stay tuned for more preparedness posts during September, which is after all Preparedness Month.