  Given a strict simple degeneration $f \colon X\to C$ the first three authors
previously constructed a degeneration $I^n_{X/C} \to C$ of the relative degree
$n$ Hilbert scheme of $0$-dimensional subschemes. In this paper we investigate
the geometry of this degeneration, in particular when the fibre dimension of
$f$ is at most $2$. In this case we show that $I^n_{X/C} \to C$ is a dlt model.
This is even a good minimal dlt model if $f \colon X \to C$ has this property.
We compute the dual complex of the central fibre $(I^n_{X/C})_0$ and relate
this to the essential skeleton of the generic fibre. For a type II degeneration
of $K3$ surfaces we show that the stack ${\mathcal I}^n_{X/C} \to C$ carries a
nowhere degenerate relative logarithmic $2$-form. Finally we discuss the
relationship of our degeneration with the constructions of Nagai.
