wrote:

What about a softer board makes it better in deep powder?

In powder you're not turning on edge, you're turning on the base with a
lot less support than an edge on hardpack. A softer board will flex and
turn more easily, plus a softer nose lets it float to the top. The
powder-specific designs all have really soft noses, so when you get them
at speed on hardpack they tend to flap around. Stiff boards need to be
steered more in powder rather than ridden, and narrow boards tend to
sink. So stiff and narrow like a raceboard is not so good for powder,
but people can still do it.

Neil