  The affine Deligne-Lusztig variety $X_w(b)$ in the affine flag variety of a
reductive group $\mathbb G$ depends on two parameters: the $\sigma$-conjugacy
class $[b]$ and the element $w$ in the Iwahori-Weyl group $\tilde W$ of
$\mathbb G$. In this paper, for any given $\sigma$-conjugacy class $[b]$, we
determine the nonemptiness pattern and the dimension formula of $X_w(b)$ for
most $w \in \tilde W$.
