what is storm damage and how can it effect a bat by the way?
Windy conditions cause some trees(ones without wind protection) to blow, bending and moving excessively, this create small weak points in the willow.
On a bat this manifest itself as small lines. Visible to a trained Person.
It can weaken the blade to a point it will snap on impact(I.e carberry in the ashes, Plunkett recently in dramatic fashion. But on other occasions it will last a few years and never give issues.
A gamble some will take for a cut down price, as they do tend to perform well up until the inevitable.