Droughts are a part of the climate, just like hurricanes, thunderstorms, and tornadoes. Unlike the other hazards that affect the state, droughts can impact large areas and last for months, or even years. A drought is defined as the lack of soil moisture over a period of time. This lack of moisture can be due to reduced precipitation, increased evaporation and/or transpiration, or higher temperatures. It can also be caused by a combination of all of these causes.
Numerous droughts stand out for having an impact in Louisiana due to the area affected and the duration of the droughts; including ones that occurred back in the mid-1920s and 1950s, along with more recent droughts observed in 2005 and 2011. During these droughts, lack of rainfall caused stream flows along some of the major river systems across the state to be the lowest on record, causing water resource shortages and loss of crops. Examine the precipitation chart on Slide 17 to see if you can find these droughts reflected in the data.