Why are mudflows so dangerous?
They happen so quickly, usually during very heavy rainfall events. People don't have time to get out of the way and many people often die in these slides.
Mudslides happen when a tipping point is reached in terms of saturated ground from heavy rains. All of a sudden, the ground is saturated enough that frictional and other cohesive forces are overcome, gravity takes over and a mass of ground gives way and slides. Very hard to predict where and when these slides will occur. Areas of high elevation, with a loose kind of subsoil and areas of heavy rain are high risk areas.