Trekking season should be just about finished, but yes climbing season is beginning so there will be a lot of climbers on Everest. I had not seen the 18 number you referenced. Horrible if that turns out to be accurate.
Pretty early for real data on something this big.
The quake triggered an avalanche on Mount Everest, killing at least eight people, and another five in Tibet, officials and reports say.
http://www.bbc.com/news/world-asia-32461019