The formation of the bum cloud, a heavy brown mammatus hovering at 3000 meters, was a ghastly sight. It was dotted with dark lumps and curved around like a buttock. A strange, foul whiff lingered in the air, nothing like they have ever encountered. The wild flowers wilted away. The marmots retreated into their deep burrows. Caterpillars crawled to the underside of the leaves that they…