An automatic warning system may be installed on the slope or the retaining structures to minimize the casualties in the case the landslide should occur. In general, the slope failure warning system may be consisted of five major units, there are sensor, data acquisition, data transmission, alarm and power supply units. In addition, a proper emergency action plan should be comprehended to prevent from being panic when the alarm is triggered. A practical case is presented herein to further describe the details of the automatic warning systems.