How Singapore flight's 400-foot drop happened within minutes

Rattled travellers and crew landed in Singapore Wednesday after a terrifying high-altitude plunge on a flight from London during which an elderly passenger died and more than 80 were injured. Singapore Airlines flight SQ321 hit "sudden extreme turbulence" over Myanmar 10 hours into its journey on Tuesday, abruptly rising and plunging several times.

from Times of India https://timesofindia.indiatimes.com/world/rest-of-world/air-turbulence-singapore-airlines-flights-400-foot-rise-and-drop-within-minutes-how-it-happened/articleshow/110324673.cms