  Mirror symmetry of Calabi-Yau manifolds can be understood via a Legendre
duality between a pair of certain affine manifolds with singularities called
tropical manifolds. In this article, we study conifold transitions from the
point of view of Gross and Siebert. We introduce the notions of tropical nodal
singularity, tropical conifolds, tropical resolutions and smoothings. We
interpret known global obstructions to the complex smoothing and symplectic
small resolution of compact nodal Calabi-Yaus in terms of certain tropical
$2$-cycles containing the nodes in their associated tropical conifolds. We
prove that the existence of such cycles implies the simultaneous vanishing of
the obstruction to smoothing the original Calabi-Yau \emph{and} to resolving
its mirror. We formulate a conjecture suggesting that the existence of these
cycles should imply that the tropical conifold can be resolved and its mirror
can be smoothed, thus showing that the mirror of the resolution is a smoothing.
We partially prove the conjecture for certain configurations of nodes and for
some interesting examples.
