Sudden drought, a phenomenon that dries up the land in a matter of weeks

If sudden floods were one side of a coin, the other side or antithesis, in a way, would be sudden drought. After all, both the excess and the absence of water, capable of resurrecting images of unfortunate memory, can be equally detrimental.

However, drought has often been associated with a slow and gradual process that arrives silently. It is an episode in which the prolonged absence of precipitation becomes the dominant feature. Nevertheless, something is starting to change.

What is a sudden drought or flash drought?

Droughts have accompanied the course of humanity for centuries. They have contributed to triggering famines and have been a significant factor in the outbreak of various socio-political conflicts. Although still a matter of debate, one of the recent examples of how droughts can contribute to the destabilization of a country could be Syria.

Drought is an extremely complex phenomenon characterized by the absence of water. However, unlike other meteorological events (such as hurricanes, for example), it does not have a defined beginning and end.

Moreover, until now, one of its main characteristics was its slow development. But this particularity is changing sudden droughts can become apparent in as little as four weeks.

In the following compilation, which corresponds to the sudden drought experienced in the southeastern United States in 2019, it is clearly visible. The maps reflect the increase in evaporative stress, that is, the strain on vegetation due to lack of water, in a matter of weeks.

Evidence of an emerging sudden drought

Sudden droughts, like conventional droughts, begin with a shortage of precipitation. However, Chen et al. (1) argue that other factors are also recurrently observed:

  • Abrupt and anomalous decreases in evapotranspiration and soil moisture (as moisture decreases, evapotranspiration also decreases as plants try to conserve water).
  • Higher-than-normal temperatures.
  • Increased wind or higher-than-usual solar radiation.

These indicators could serve as early warning variables. Therefore, continuous monitoring is one of the key tools to address this phenomenon. The importance of this aspect was also highlighted during a virtual workshop held in December 2020.

Sudden droughts in Spain

Although the identification of this phenomenon was made in the early 2000s in the United States, Spain also experiences its consequences.

In fact, approximately 40% of all droughts can be considered sudden. Interestingly, the areas with the highest incidence are the northern and northwestern regions of the country, especially during the summer months (2).

However, further studies are needed, as most of the research conducted so far has focused on conventional droughts, leaving sudden droughts aside.

The tools offered by Arantec to address the issue of sudden droughts

As you can see, monitoring is essential and is one of the key tools for making decisions based on local and reliable data. On one hand, it allows for receiving alerts in case of any anomaly. On the other hand, it reduces the consumption of available water, making its use more efficient.

For example, soil moisture sensors could be used to notify when the soil is dry and irrigation is needed. These devices can be combined with our hydro-meteorological solution, Smarty River, which was awarded second prize in the Smart Catalonia Challenge 2021. It incorporates information about drought risk and also monitors hyperlocal weather conditions.

The water-saving aspect would come hand in hand with supply control systems. Some successful cases include the installations in the town of Les, the water reservoirs of Vielha e Mijaran, and Salamanca. In this way, early problems that could compromise water supply could be detected, thus helping to conserve water consumption during periods of scarce rainfall.


One of the main conclusions we can draw is the need to value real-time and continuous monitoring. It is evident that this is one of the main tools we have to alert about the onset of a sudden drought.

Furthermore, it is highly likely that the occurrence and impacts of these phenomena will be exacerbated due to climate change. After all, one of the aspects that is clearly evident with this alteration of the usual climate patterns is the change in precipitation regimes.

We have the tools. We have the knowledge to make the most of them. We just need to be aware of the problem and apply some creativity, as highlighted in this article.

And imagination is precisely one of the hallmarks of Arantec.

Sources consulted:

  • (1) Chen, L., Gottschalck, J., Hartman, A., Miskus, D., Tinker, R., & Artusa, A. (2019). Flash Drought Characteristics Based on U.S. Drought Monitor. Atmosphere, 10(9), 498.
  • (2) Noguera, I., Domínguez‐Castro, F., & Vicente‐Serrano, S. (2020). Characteristics and trends of flash droughts in Spain, 1961–2018. Annals Of The New York Academy Of Sciences, 1472(1), 155-172.

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