Sometimes...what you can't see is what will kill ya
Seriosuly though.
Wind shear occurs when an aircraft passes through air that travels in different directions and velocity. It's very common, happens all the time at all altitudes.
Even though it's seldom dangerous things can get bad when facing violent wind shear at low altitudes. If that's the case then it's definetely an hazard during take-offs and landnings.

Imagine this:
An aircraft is about to land but suddenly encounters a strong hedwind. The speed increases (Airspeed) and more lift is created by the air flowing over the wings. The pilot now has to reduce speed and altitude in order to maintain the glideslope. If the aircraft now encounters a tailwind the speed will drop and the aircraft starts to lose altitude - fast.
This is likely to happen in micro bursts which is developed in thunderstorms. Think of a a micro burst as water pooring from a tap in a bath tub: It rushes down, hits the ground, scatters and bounces up again The air will behave in the same way.

I assume you were reading about the NWA DC9?
Boneheaded pilot that tried 3 times to get the aircraft down, he's not a hero...

I don't know about the old Dc niners, but newer aircrafts has a wind shear warning system that detects this. It will sometimes give false alarms...when flying towards a hill or slope at low altitudes (Madeira for example). As you're facing the hill, the aircraft will detect moving targets on the hill and alert the pilots.

But the system is designed to safe lives and has almost eliminated these kind of accidents since the mid 80's.