The Horrifying Power of Mudslides

Over the weekend, a mudslide killed at least 8 people in the state of Washington, with 108 people missing or unaccounted for. Hopes of finding any more survivors from the massive mudslide waned as rescue workers pulled more bodies from the debris field as they work to locate more survivors.

View of the Washington mudslide:

We didn’t see or hear any signs of life out there today,” Snohomish County Fire District 21 Chief Travis Hots said. “It’s very disappointing to all emergency responders on scene.” The 1-square-mile slide critically injured several people – including an infant – and destroyed about 30 homes.

Crews were able to get to the soupy, tree-strewn area that was 15-feet deep in places Sunday after geologists flew over in a helicopter and determined it was safe enough for emergency responders and technical rescue personnel to search for possible survivors, Hots said.

Officials described the mudslide as “a big wall of mud and debris” and believe it was caused by ground made unstable by recent heavy rainfall. It blocked about a mile of State Route 530 near the town of Oso, about 55 miles north of Seattle. Searchers will continue their efforts through the difficult debris field.

Witness the power a mudslide can have (jump to 0:35):

Here’s what you need to know about mudslides:

According to, heavy rains aren’t the only factor that can trigger a mudslide. A sub-category of landslides, mudslides are rivers of rock, earth and other debris that are saturated with water.

  • Mudslides can be slow- or fast- moving, though they tend to grow in size and momentum as they pick up trees, boulders, cars and other materials.
  • Mudslides can occur at any time of the year, regardless of weather conditions, according to the Federal Emergency Management Agency (FEMA). And they can strike without any prior warning signs, making for a dangerous phenomenon.
  • Mudslides occur in all 50 U.S. states and can happen at any time – with or without rainfall.
  • Earthquakes, volcanic eruptions, changes in groundwater levels, alternate freezing and thawing, and the steepening of slopes by erosion all contribute to mudslides.
  • Construction and reckless modification of land – such as not draining an area properly before building on or near it – can also create the conditions ripe for a mudslide.
  • Prolonged, intense precipitation and run-off can contribute to landslides, as can wildfires. Fires lead to mudslides because burning can kills the plants’ roots. Roots hold soil together, stabilizing the land and making it less likely to be swept away, according to Highland. In this way, overgrazing can also contribute to mudslides.

WeatherBug is saddened by the tragic loss of life, and hopes for a speedy recovery in Washington.

Stay Safe. Know Before™.

The WeatherBug – Earth Networks Team

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