Drought definitions

Drought evolves through an extended period of dryness, as a scarcity of precipitation progressively depletes the supply of water available in the soil, streams, lakes and reservoirs, and even aquifers. The rate of depletion depends upon the demand for water, combining both the loss of water to the atmosphere through evapotranspiration and the consumption of water for societal needs. Flash drought reflects the rapid onset of dryness during the warm season when high temperatures and low humidity increase the demand for water and accelerate the development of drought conditions.