This story tells us just one of the reasons why we do not fly into clouds. Actually, by the FCC laws, we must stay more than 500' below any cloudbase. However, we do get "whited-out" from time to time((by accident))! Just in case someone official is monitoring, haha. Just Kidding.

Paraglider survives after soaring to 32,000 feet A German paraglider was encased in ice and blacked out after being sucked into a tornado-like thunderstorm in Australia and carried to a height greater than Mount Everest . She survived.
http://www.msnbc.msn.com/id/17185299/from/ET/