What Is Drought? Discover All Types of Drought

The first drought type is an agricultural drought. It mostly concerns farmers and others in agricultural occupations more so than the general public. Whether there is a widespread drought or not, an agricultural drought occurs when there’s a shortage of water at the time in a crop’s growth cycle that it needs water most. For instance, if it’s been particularly dry when a crop is planted, that might affect the rate at which those plants reach maturity, and that can negatively affect the crop yield. On the other hand, if there’s plenty of moisture at initial planting but not enough later in the growth cycle, that crop still has a fighting chance . Hence, there can be a water shortage later in a crop’s lifecycle without that shortage qualifying as a drought.

The number of agricultural droughts is also going up thanks to good ol’ climate change. As the earth warms, snow is melting earlier in the year and in some cases, precipitation that would have been snow never even makes it that far and falls instead as rain. Both those scenarios lead to faster water run-off. Faster runoff means moisture that would have been available later in the cycle becomes unavailable when plants actually need it.

The second drought type is called meteorological. This is your “drought classic” — it’s the kind most of us think of when we hear that word — a long dry period with no rain or snow. Because it depends on the comparison of the actual rainfall in a given year against the average, meteorological droughts are considered highly “region specific,” as the National Drought Mitigation Center (NDMC) puts it. Basically, that means the definition of a drought in a rainforest is far different from the definition of one in a more arid climate like a desert. So, it’s sort of like a flu strain that only has a few of the worst symptoms.

Third, we come to hydrological drought. This little bugger occurs when the amount of snow and rainfall in a given area drops for an extended period of time, leading to lower amounts of available water in both surface water (rivers, streams, reservoirs) and subsurface water (aquifers, wells, that pesky water table we all hear so much about). Here, hydrologists are concerned with the way the shortage of precipitation plays out further down the ecological chain. According to the NDMC , “It takes longer for precipitation deficiencies to show up in components of the hydrological system such as soil moisture, streamflow, and groundwater and reservoir levels.” They further point out that when water is stored within a given basin, there are multiple competing demands for it.