The theory that weather modification can be used as a weapon has been around for many decades. The U.N. members signed a treaty long ago agreeing that no country could use weather as a weapon. However some theorize this has been ignored with the existence of HAARP. Which is a mysterious government operation that conducts experiments on the Ionosphere and many theorize that it is capable of controlling the weather and is capable of intensifying hurricanes, causing droughts, floods and even earthquakes.
Weather modification is the act of intentionally manipulating or altering the weather. The most common form of weather modification is cloud seeding to increase rain or snow, usually for the purpose of increasing the local water supply. Weather modification can also have the goal of preventing damaging weather, such as hail or hurricanes, from occurring; or of provoking damaging weather against the enemy, as a tactic of military or economic warfare. Weather modification in warfare has been banned by the United Nations. - Source: Wikipedia