In August and September 2015, a massive dust storm swept across the Middle East, engulfing seven nations in sand thick enough to ground flights, trigger respiratory distress for many, and obscure the region from satellites. At the time, the unprecedented size of the storm was blamed on the ongoing conflict in Syria, with unusual amounts of dust being raised from abandoned agricultural lands and increased military traffic. But a new study cites a combination of climatic factors and weather as the more likely culprits.