Thirty years ago I took part in an attempt to ascend an unclimbed route on Mt Everest (NE Ridge).
Our trip was during the post monsoon period (August-September). While we did have a period of good weather, snowfall became mostly non stop. At the end of August jetstream winds descended. No expedition attempting routes on the northern side of the mountain was able to summited that season.
The route we attempted was the same route Peter Boardman and Joe Tasker died on. In subsequent years I believe climbers have made it through a series of pinnacles, but no one has summitted via this route.
Article: https://lmtribune.com/northwest/last-men-on-the-mountain/article_962a9909-5920-52f9-9413-3a857cf43f3f.html?utm_medium=social&utm_source=facebook&utm_campaign=user-share&fbclid=IwAR3eywumm7VM5nSMLcUJQRzbyt_KQ2tlTbKcSZPQW9Qb9u2Tdf13X6XHLbs
It was interesting/depressing to see how some of the Chinese liaison officers treated Tibetans.
When we new we were not going to summit, two brits and myself did a 20 mile walk down the road. We told others not to say anything to the main liaison officer until trucks scheduled to drive us to Nepal showed up.
Once the liaison officer caught up with us, he was a bit pissed.