Everest traffic has increased in recent years because expeditions have become more popular.

"Traffic jams" caused by unprepared climbers who "do not have the physical condition" for the journey

The most dangerous part is often the descent.  A lot of people push themselves to the summit, but, once they reach it, "lose their motivation and energy on the way down", especially when they realize it's a long, crowded journey.

Records suggest there have been just over 280 deaths on the mountain.

Sometimes, oxygen cylinders left out for designated climbers get stolen.  "When you have winds of stronger than 9 mph, you just can't make it without oxygen... you're losing so much body warmth"; jet stream winds are at 20,000 - 50,000 feet elevation.

Climbers sometimes queue between 20 minutes, and 1.5 hours, in order to reach the summit.

It often depends on how long the window for suitable climbing weather is - because mountaineers need to avoid fierce jet streams that would hinder them.  "If there's one week [of safe weather], then the summit isn't crowded. But sometimes, when there's only a window of two or three days, it gets very crowded" as all the climbers try to reach the summit at the same time.