Blizzards, Thunderstorms, Lightning, Tornadoes, Tropical Cyclone, Drought, Hailstorm, Frost, Heat Wave or Loo.Cold Waves, etc.
Earthquakes, Volcanic Eruptions, Landslides, Avalanches, Subsidence, Soil Erosion.
Floods, Tidal Waves, Ocean Currents, Storm Surge, Tsunami.
Plants and Animals as colonisers (Locusts, etc.). Insects infestation— fungal, bacterial and viral diseases such as bird flu, dengue, etc.