According to recent findings, during the last interglacial period, about 120,000 years ago, the precursor of the Dead Sea (Lake Lisan) dried up perhaps entirely. Today, the Dead Sea level is dropping at rates of around >1m/year from the countries surrounding the Sea using all the runoff. Future climate change scenarios for the region suggest even more arid conditions. Even though previous studies suggested that the decrease in water level would stabilize around 100-150 m below current conditions, the Goldstein et al. (2011) core evidence might suggest otherwise. Could the Dead Sea dry up? What conditions could lead to such an extreme? When would that occur?
The Dead Sea salt is almost equally Mg-chloride and Na-chloride at about four times normal sea-salt salinity. This combination is extremely hygroscopic whilst, at this ultra low elevation and high temperature, there is very high humidity. People who try to towel themselves dry after swimming in the Dead Sea find that they can't - the salt absorbs atmospheric moisture as fast as they can towel it off. In addition to the chemical characteristics of the salt, at such high concentrations the water vapour pressure at the liquid surface is almost nothing. Therefore, it will require extreme and very prolonged dessiccation to dry out the Dead Sea completely. On the other hand the sea-level still has a long way to drop before it becomes a sort of slushy paste.
Lately, a couple of scientific discussions came up and challenged the conclusions of Goldstein et al., 2011 (see Katz & Starinsky comments to Torfsteins’s et al., (2015) paper, in EPSL) A recent paper by Neugebauer et al. (2015) published in Climate of the Past discussions, interprets the gravel layer (which was presented as the main evidence for dry up or at least massive drawdown of the lake) as an artifact of the drilling process. So it seems that there is today no evidence for a complete dry up of the paleo Dead Sea.