The Natural History and Dangers of the Rub' Al-Khali:
The size of France, Belgium, and the Netherlands combined, The Empty Quarter is the largest contiguous sand dune desert in the world, an area as dangerous - and logistically more difficult to cross - than Antarctica. If an accident had befallen anyone, no helicopter or fixed-wing aircraft could have ever reached us because of density-altitude problems and the fact that it is covered by contiguous sand dunes. A helicopter cannot operate over any significant distance, not with any real load, in temperatures of 40-61C.
The Empty Quarter is populated by huge 150-km-long 'Irq ("vein") dunes, 700 meter-high horned Barchan dunes, wall-like Zibar dunes blocking movement down the Shugs (corridors between 'Irq dunes). There are also large areas of lag-gravel plains with seif ("sword") dunes marching across them. In the eastern margins there are sabkhas: dry-crusted, lithium-rich brine-mud lakes. We measured temperatures to 61 degrees C. (142 degrees F.) on the first Zahid Expedition, and encountered humidities down to 2% (20% is considered extremely dry in the southwestern US). Around the edges of the Empty Quarter we encountered 10-cm-long jerboas, 15-cm-wide camel-spiders, meter-long sand-vipers, and 10-cm-long, translucent scorpions; the central core of the desert, where even Murra tribesmen don't venture, was absolutely lifeless. We also found thousands of ancient dried lakes in two different levels between the huge 'Irq dunes, clear evidence of two previous pluvial periods, elegant flint arrow-heads, and evidence of huge water-buffalo-like bovids (see photo of skull, fresh-water molluscs, and arrow-heads on the Zahid Expedition page). This ancient Land of 10,000 Lakes had human dwellers, even hippos.
Life for us in the Empty Quarter followed a routine of morning ablutions from a canteen, a light breakfast, then we would pack our Hummer vehicles and move on, typically covering 250 to 500 km before our next camp-site. We brought all our water and all our fuel with us: 700 litres of diesel per Hummer, 100 litres of water per person. The average weight of each Hummer was thus about 11,800 lbs (5.4 metric tons). The temperatures reached 55-61 degrees C (130-142 degrees F) during the day, and some of our vehicle airconditioners failed from the terrible overload... in those vehicles, moving wind was the only coolant, and we rotated seats because a day in that heat would exhaust everyone. For 10 months out of the year, the winds in the Rub' Al-Khali pick up around noon local time from the north-northeast and reach a screeching crescendo around sunset; during the February-March Arabian Sea monsoon season, the winds reverse direction and come from the south-southwest. As the sun would set, we would set up tents in the late afternoon sand-storm, some of us wearing swim-goggles to protect our contacts from the stinging grit. Dinner was almost always mixed with flying sand; you could feel it grinding in your teeth: sand-burgers, grit-goulash, sand-pudding. Sleeping at night consisted of first securing the tent against scorpions and camel-spiders, which would leave tracks during the night showing that they were constantly searching for a way in. We then slept on top of our sleeping bags - the temperature normally didn't go below 40 degrees C (100 degrees F) during the night. We had to carefully brush the grit from our eyes before we dared to open them, and burning throats in the extremely dry conditions (down to 2% humidity) forced us to drink from our individually-issued water-jugs at least 5 times every night.
In the profound, windless silence of the mornings, I walked into the desert with a still and a video-camera to photograph the tracks left in the sand: a mute record of the life-and-death struggles that took place during the night between lizards and snakes, scorpions and camel-spiders, dung-beetles and jerboas. By sunrise, everything that had survived the night was already under the sands again in a high-temperature hibernation. What feeds this ecosystem? Insects blown in from the Gulf and the distant mountains by the diurnal sandstorms. What plants we found were either dessicated or had waxy coats on the needles to protect what moisture they had. We never saw any evidence of plant predation in the core of the 'Rub al-Khali.
The harsh survival-mode existence we lived under, and working shoulder-to-shoulder, cemented permanent bonds of friendship among us, a comaraderie that crossed cultural and religious barriers. It was not quite devoid of humor, the exhaustion at the end of each day notwithstanding.
Beyond the circle of our tents stretched the featureless, rolling dunes of the emptiest place on earth, looking for all the world like the great rollers of the North Atlantic, only motionless - and white.