Windshear - сдвиг ветра. Резкое изменение направления или скорости ветра.
Microburst - мощный нисходящий поток. Вот как это явление описывает FAA Pilot Handbook of Aerodynamic Knowledge:
"One critical type of shear associated with convective precipitation is known as a microburst. A typical microburst occurs in a space of less than 1 mile horizontally and within 1,000 feet vertically. The lifespan of a microburst is about 15 minutes during which it can produce downdrafts of up to 6,000 feet per minute. It can also produce a hazardous wind direction change of 45 knots or more, in a matter of seconds. When encountered close to the ground, these excessive downdrafts and rapid changes in wind direction can produce a situation in which it is difficult to control the aircraft. During an inadvertent takeoff into a microburst, the plane first experiences a performance-increasing headwind, followed by performance-decreasing downdrafts. Then the wind rapidly shears to a tailwind, and can result in terrain impact or flight dangerously close to the ground. Microbursts are often difficult to detect because they occur in a relatively confined area."