19 Mudslide Facts: Learn More About These Natural Disasters

A mudslide, also known as a 'mudflow', or 'debris flow', is a significant natural hazard that occurs in practically every state in the United States.

Mudslides can happen without warning and cause severe damage in the affected area. As people move to new hilly and mountain locations, it is even more crucial that they understand what causes landslides as these areas are more vulnerable to this natural disaster.

Although the physical causes of landslides, such as volcanoes, earthquakes, and heavy rainfall, cannot be avoided, safety precautions and efficient land management can help to mitigate the devastating effects of mudslides. Continue reading to learn everything there is to know about mudslides and how to deal with them if they occur in your area.

Meaning Of Mudslide

Mudslides are a type of landslide that is distinguished by the mass flow of debris, mud, or rock down a slope.

• A mudslide is a form of landslide that moves quickly and transports vast volumes of rocks, debris, and other suspended particles along a channel on a steep slope.
• Mudslides, like other types of landslides, work on the principle of gravity. The Earth pulls the ground downward, causing rocks and debris to fall at rapid speeds. They can even uproot trees.
• Landslides are caused by various factors, including severe rainfall, human modification, wildfires, earthquakes, volcanoes, slope cuts, and erosion.
• A considerable volume of mud and debris carried down a hill slope by mudslides is capable of causing severe damage and destruction and may even result in death.
• Some ailments induced by mudslides and landslides include trauma from swiftly moving water and broken sewage, electrical, gas, and water lines, which can lead to other infections.
• The deadly mudslides that happened in Venezuela in December 1999 were among the worst in world history. The mudslides caused widespread devastation, and about 10% of the state's population perished as a result of the unfortunate event.
• In 1985, a mudslide was triggered by the volcanic eruption of the Nevado del Ruiz stratovolcano in Colombia. It resulted in the death of most of the population in Armero town (20,000 out of 29,000 residents).
• In 1934, a mudslide in the United States' La Crescenta Valley destroyed more than 400 dwellings. This mudslide was caused by intense rainfall and wildfire in the Angeles National Forest.
• During the last 6,000 years, at least five massive landslides have raced down the slopes of Mount Rainier in Washington.
• In the United States, landslides and mudslides lead to 25-50 casualties and cause damage worth USD 3.5 billion every year.
• California is regarded as extremely susceptible to mudslides since it possesses all of the potential mudslide triggers, such as earthquakes, wildfires, and rainfall.

Characteristics Of Mudslides

As the name suggests, mudslides carry a lot of mud, debris, and rocks while they flow down the slopes of mountains and hills, causing the risk of casualties.

• Landslides occur not only on Earth but also on other planets in the Solar System, such as Venus and Mars, which may be seen by satellites.
• Mudslides are a kind of landslide and are divided into two types: mudflow and debris flow. While mudflow involves the movement of water and mud, debris flow includes the movement of mud and large rocks suspended in water.
• When water rapidly accumulates in the ground, it causes a surge of water-saturated dirt, rock, and debris leading to a mudslide. Mudslides are typically caused by natural disasters and originate on steep slopes.
• Mudslides usually begin as shallow landslides that liquefy and intensify as they proceed down a steep slope.
• A lahar is a specific type of mudflow that is made up of volcanic debris, mud, water, and rocks. It flows down river valleys at speeds ranging from 20-40 mph (32-64 kph).
• Lahars can travel more than 50 mi (80 km).
• Tsunamis can also be caused by landslides. This is most commonly seen when a volcano or an island collapses underwater. It triggers tsunamis by pushing the water upward.
• Five tsunamis occurred in Alaska in 1964 as a result of submarine landslides caused by an earthquake.
• Even scientists are unable to predict how long a landslide or mudslide will persist.
• Landslides are also difficult to predict due to changes in soil composition and other regional features.
• Landslides are thought to be extremely dangerous since they occur without any warning signs.
• Heavy rains are the most common cause of mudslides. Other causes include earthquakes, slope steepening due to erosion, volcanic eruptions, and abrupt temperature changes.
• Mudslides can be exacerbated by wildfires. This is because the heat, oily residue, and ash produced by wildfires make it impossible for the top layer of soil to absorb water. As a result, instead of absorbing water, the soil travels down the slope.
• Hillsides are more exposed to landslides after a wildfire for three to five years because vegetation takes a long time to regenerate.
• Mudslides have been known to travel considerable distances from their site of origin.
• Stream channels, canyon bottoms, slopes cut for roads and buildings, locations with less vegetation, and sites where landslides have previously occurred are the most vulnerable to mudslides.
• Areas that are less prone to landslides are regions where landslides have not occurred in the past and flat areas that are at a distance from slopes.
• While landslides cannot be foreseen or prevented, some characteristics may arise before the occurrence of a landslide. These include new ground fractures, earth moving away from its foundation, cracks in flooring, and structural tilting.
• There is no specific season when landslides and mudslides occur. They can occur at any moment during the year.
• Mudslides can move at either a slow or quick pace. They do, however, gather momentum as they continue to travel. They usually travel at a speed of 50 mph (80 kph).

Reasons For Mudslides

Mudslides can develop due to several reasons. They usually accompany volcanic eruptions, wildfires, heavy rain, erosion, and earthquakes.

• Heavy rain is the most common cause of mudslides.
• When human modification, such as deforestation and construction, removes vegetation on hill slopes, these places become vulnerable to mudslides because the vegetation that keeps the soil together and prevents it from moving is gone.
• Loss of vegetation cover due to wildfires also makes the land prone to mudslides and erosion, especially during and after a major storm.
• Mudslides caused by volcanic eruptions can be mild, involving small movements of loose debris, or catastrophic, involving the complete collapse of a volcano's sides.
• As steep volcanoes are made up of layers of loose volcanic rock fragments, they are more prone to landslides.
• Lahars are the most dangerous mudslides, capable of destroying the entire surrounding area. They can occur during an eruption as well as while a volcano is dormant.
• Lahars are formed by water from melting snow and ice, heavy rainfall, or the eruption of a summit crater lake.
• Earthquake-caused landslides can also be quite devastating.

Safety Tips For Mudslides

Mudslides and landslides can neither be prevented nor predicted well in advance. However, numerous steps can be taken to ensure that the damage caused by the landslide is minimum. Special care must be taken before a major storm or heavy rains to avoid risk.

• Keep in mind that places prone to wildfires and steep slopes are more prone to landslides and mudslides.
• Inquire with officials and prior residents to learn if landslides have occurred in the area in the past. Landslides are more probable to happen in areas that have previously experienced them.
• Consult the local authorities with the entire community to develop evacuation and emergency plans.
• Create evacuation and emergency preparations for yourself and your family.
• Gather all relevant emergency contact information and distribute it to everyone in the family. This will be useful if somebody gets separated.
• Collect all necessary emergency communication numbers and distribute them to everyone in the family. This will help in case anyone gets separated.
• Move to a safer area.
• During severe rains, watch television or listen to the radio to stay up to date on local authorities' warnings and advice.
• Keep a close eye out for any changes in the water level in the region.
• Look for landslide warning indicators such as tilted trees, cracks in floors, and so on.
• Keep an ear out for any rumbling sounds you may hear. It can signal the onset of a mudslide or landslide.
• Drive with caution in heavy rain because roads may become inaccessible due to debris collapse.
• If you are caught in a mudslide, get out of the mudflow's path as quickly as possible and run for safety.
• Don't enter the affected land area after a landslide has occurred because more slides or floods may occur.
• If there are injured or trapped people near the impacted area, attempt to help them but keep away from the mudslide's path.
• Check for broken utility wires and notify the appropriate authorities.
• Plant trees as soon as possible in affected areas especially after mudslides triggered by wildfires.