Answer:
Before a storm ---> Find out the mudslide evacuation plans from local authorities (doign this means you're aware of how/when to evacuate if there's a mudslide)
During a storm ---> Notice when the water levels of nearby creeks or streams begin to rise. (you're paying attention to the water in case there's a mudslide or flood)
After a mudslide ---> Look for injured or trapped people. (you wanna alert the authorities and get these people some help)