[August]

Nope not the first and not unique either:

https://en.wikipedia.org/wiki/1972_A...light_disaster

Uruguayan Air Force Flight 571 was a chartered flight carrying 45 people, including a rugby union team, their friends, family and associates, that crashed in the Andes on 13 October 1972, in an incident known as the Andes flight disaster and, in the Hispanic world and South America, as the Miracle of the Andes (El Milagro de los Andes). More than a quarter of the passengers died in the crash and several others quickly succumbed to cold and injury. Of the 27 who were alive a few days after the accident, another eight were killed by an avalanche that swept over their shelter in the wreckage. The last 16 survivors were rescued on 23 December 1972, more than two months after the crash.