Why was the march through Gedrosia so deadly for Alexander the Great’s forces?

The march through Gedrosia (modern-day Baluchistan) in 325 BCE was a catastrophic endeavor for Alexander the Great’s forces, resulting in significant loss of life.12

The disaster was driven by several critical factors:

• Environmental Extremes: The army faced a waterless desert characterized by severe shortages of food and fuel, which caused immense suffering among the troops.1
• Logistical Failure: Alexander intended to establish food depots for the fleet commanded by Nearchus, but the mountainous terrain forced him to turn inland, rendering the plan impossible.1
• Natural Disasters: While encamped in a wadi, many soldiers—particularly women and children—perished during a sudden monsoon flood.1

Historians suggest that the scale of this tragedy may indicate that Alexander’s judgment was impaired at the time, possibly motivated by a desire to surpass the legendary feats of Cyrus the Great and the mythical queen Semiramis. Ultimately, the march is remembered as a "death march" that inflicted heavy casualties on both the land forces and the accompanying fleet.31