What is it like flying through a torrential downpour?

The carwash is a good ogy. In a "torrential downpour" you cannot see anything, or extremely little, even with the wipers or other rain-shedding devices operating at maximum. Thats what flight instruments are for. Because severe downdrafts are sometimes ociated with a torrential downpour, pilots usually avoid taking off or landing in such conditions and generally try to avoid heavy rain while enroute because of the turbulence often ociated with it. However, one can takeoff and land in moderate to heavy rain in the right conditions and it happens all the time, just not in a "torrential downpour" which often reduces the visibility below legal landing minimums.