The current situation in Venezuela, with drought leading to a shortage of hydropower, is a great example of a problem with the word “drought.” A reminder of Kelly Redmond’s handy definition:

Most concepts of drought involve a water balance. This implies that both supply and demand must be considered, as well as the question of whether there is enough (and, enough for what?). Thus, through time I have come to favor a simple definition; that is, insufficient water to meet needs.

The Venezuelan case is an intriguing one because it’s not the shortage of water itself that’s causing all the problems, but rather the shortage of electricity the water was used to generate. But like all “drought”, Redmond’s definition makes the crucial point that both supply and demand matter. And as Marianna Parraga reports for Reuters, what’s happening in Venezuela right now is in significant part a demand side drought:

A severe drought has forced Venezuela President Hugo Chavez to ration electricity in South America’s top oil exporter, but underinvestment and shortsighted planning during an economic boom are as much to blame as the weather.

Cities and villages are without light for hours at a time since rolling blackouts began last week in a desperate bid to stop water levels dropping further in the dams that provide more then two-thirds of the South American nation’s power.

The first day of electricity rationing in Caracas was particularly chaotic. Schools, medical centers, street lights and traffic lights were without power, forcing Chavez to order a suspension of the rationing.

The program follows a dozen unplanned outages that affected large swathes of the country, spotlighting a crisis stemming from a demand surge that has not been matched by new supply.

Variability happens on the supply side. If you are not robust to the dry side of the normal range, and you allow demand to rise during wet times, trouble is inevitable.