I'm obliged to an anonymous reader for sending me the link to the first video below.
Microbursts pose a deadly danger to aircraft on final approach to a runway. This video shows a microburst over Tucson, AZ earlier this month. It's the clearest example I've ever seen of this weather phenomenon. Watch it in full-screen mode for the best effect.
This is the sort of localized storm that brought down Delta Air Lines Flight 191 in 1985. Here's an excerpt from a Smithsonian Channel documentary on the crash.
Miss D. informs me that it's actually easier to handle a microburst in a light aircraft like hers than it is for a jet airliner, because piston engines respond instantly to throttle demands, whereas jet engines have to 'spool up' to provide the thrust. The slight delay while doing so can contribute to a crash.