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What is a landslide?

It’s estimated that landslides and debris flows result in 25 to 50 deaths each year in the United States. Slopes and areas burned by wildfires are considered to be more vulnerable to landslides and debris flows.

By Andrew Wulfeck Source FOX Weather

What sets the stage for landslides in California?

U.S. Geological Survey Landslide Hazards Program Research Hydrologist Matthew Thomas provides insight on FOX Weather. 

A landslide is an event when a mass of rocks, vegetation or other debris moves down a slope in an uncontrollable fashion and can lead to additional hazards.

Landslides are considered to be common in mountainous areas and can be triggered by rainfall, droughts, earthquakes, or even volcanic eruptions.

According to the Centers for Disease Control and Prevention, landslides and debris flows result in 25 to 50 deaths a year, as there are no real warnings ahead of when the land can give way.

"Although the physical causes of many landslides cannot be removed, geologic investigations, good engineering practices, and effective enforcement of land-use management regulations can reduce landslide hazards. It is also important to understand the science of landslides – their causes, movement characteristics, soil properties, the geology associated with them, and where they are likely to occur," the U.S. Geological Survey stated.

LANDSLIDE DESTROYS CALIFORNIA HOMES AS SIGNIFICANT GROUND MOVEMENT THREATS CONTINUE

Recent landslides have destroyed homes in California and Alaska, with many coming without significant warning.

Geological experts said the region has a lot of young mountain ranges, and with a lot of loose soil and debris, it can lead to landslide events.

Growing cracks, sudden changes in water levels or groaning produced by the terrain are all considered to be warning signs that a landslide event could be underway.

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San Bernardino County Firefighters watched helplessly as a landslide came down around their firehouse.  (San Bernardino County Fire)

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A landslide occurred after 9 p.m. Monday, Nov. 20, just south of Pat Creek Road in Wrangell Alaska. (Alaska Dept. of Transportation)

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TOPSHOT - This aerial view taken on August 9, 2023 shows the camping site in Dokka flooded after the Dokka River overflowed its banks. Heavy rains caused flooding and landslides in Sweden and Norway on August 8 while strong winds caused a Danish wildfire to spread out of control, authorities said, with more heavy rain forecast. A storm dubbed "Hans" swept in over the Nordic countries over the weekend, leaving a path of destruction. Norway police reported several landslides in the southeast, with media reporting that over 100 people had been evacuated as a result. (Stian Lysberg Solum / NTB / AFP)

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A landslide destroyed several homes in Rolling Hills Estates in California. (Image: Janice Hahn/ LA County Board of Supervisors) ( )

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A landslide has destroyed houses in Valdres, Nord Aurdal, near Bagn, Norway on August 8, 2023, as extreme weather 'Hans' has hit eastern Norway. The Meteorological Institute has issued a red warning for very heavy rain, floods and landslides in Viken north of Oslo, Innlandet and parts of Trøndelag. (Cornelius Poppe / NTB / AFP)

7 THINGS TO KNOW ABOUT MUDSLIDES

Landslides can be referred to as rockfalls, lateral spreads, debris-flows or even mudslides and the classification typically depends on the movement of particles in the event.

Direct losses due to landslides exceed $2 billion annually, according to the Washington State Department of Natural Resources.