What do you mean by "storm" kite ???
You can IMO not really kite in a storm, with current kitesizes most brands offer, unless you are really heavy, or totally overpowered and survival only, if you are lucky
A storm kite for the average weight kitesurfer (75-80kg) should be around 2½m2 max 3 if it should be in its sweet spot on a TT
Brands make small kites for waveriding mostly, and not too small, as the worldwide "market" = sale isn't there.
Becaue some live in areas where 4 and 5m2 are not used often.
Others, like here, use these sizes relatively often - as for waveriding you use a 5 and 6m2 a lot (7 being the most used size here in waves)
This leads me to believe, that when you talk about a "storm" kite, you live in an area where 5m2 is not used much ?
Remember, a storm is over 50 knots (48-55) and this is average, so the gusts are much higher !
So for me a storm kite would be a 3m2 kite maybe.
Which I dont need as I dont kite in storms...
But I've missed a 4m2 many times, as it works fine on a waveboard in just over 30knots only, but I can just manage with a 5 almost fully depowered so that is an okay compromise, eventhough overpowered
On a TT you can hold these sizes in somewhat more wind of course.