The Colgung air Q400 was not icing related, if you watch the the FDR recreation they left the PLs at flight idle during configuration until the aircraft stalled, the reaction to the stall was what then caused the accident.
There are no aircraft that I know of certified for flight into Severe Icing Conditions.
This is correct however you will encounter severe icing on occasion without it being forecast, sometimes it's easy to get out of other times it can take a while to get to a point to shed the ice.