The storm paddle
A lot of people speak of the storm paddle as a thing in its own right. The term is also wrongly used about a regular Greenland paddle. It's hard to say how this usage came about. What's certain is that in Greenland, where one often paddled in bad weather, people often had fairly short paddles. The American kayak researcher John Heath gives the measurements of a storm paddle as about one 'arm span'. This means that a storm paddle can be about as long as the height of the user. In other words very short! The shaft is usually very thin — two hands breadths is not uncommon. The blades should be narrow, especially close to the shaft, where one is going to hold the blade when paddling. When paddling, you constantly change your grip and move the paddle from side to side, this is often known as 'the sliding stroke'. The advantage of this is to have as little of the blade as possible exposed to the wind, as well as keeping your fingers in motion against the cold. Not everybody likes this technique, but some use it just for fun and not in a storm.
Many paddlers use the stormpaddle as a spare paddle — something it's very well suited for. And in this case, the length of the kayak's foredeck should be a factor in deciding the length of the paddle. If it's suitably long, it will lie flat against the deck, and be ready for use, either as a spare or for rolling with. That said, if you carry a stormpaddle as a sparepaddle... well then you should be able to use it and be familier with the above mentioned sliding stroke.