mark, "what happened" was rare. The solo hiker either intentionally or by mistake, headed down the north side of the mountain from the summit, completely opposite from the side he came up. Nearly all fatalities are due to lone hikers heading off in the wrong direction, and that happens more frequently in the darkness while descending. The risk of those things happening are rare, and can be minimized if you are well aware of those issues.
The mountain will always be here -- stay in shape, and you can come next year. ...or later this year: Note how there are usually permits to pick up on
recreation.gov just a day or two before the hike date.