The ABCDE rule can be used to help you remember what a melanoma tumor typically looks like: 1  Asymmetry: The shape of one half of the mole does not match the other. 2  Border: The edges are ragged, notched, or blurred. 3  Color: The color is often uneven. Shades of black, brown, and tan may be present.
In many cases, heavy rains set off landslides. However, in many cases landslides may also occur in unpredictable was, such as the timing of a rockfall after a spring thaw. Sometime deep-seated slumps or mudflows will not move until days or weeks have passed after a storm.
Natural causes of landslides include: 1  groundwater (pore water) pressure acting to destabilize the slope. 2  loss or absence of vertical vegetative structure, soil nutrients, and soil structure (e.g. after a wildfire â a fire in forests lasting for 3â4 days) 3  erosion of the toe of a slope by rivers or ocean waves.