Getting out of the cave required shovels with a magical barrier over them, as the falling ash had hardened into a layer that would put the average concrete wall to shame, and the layer was over a metre thick.
That didn't bode well for what was outside, where they found that the trees had been mostly spared from the fire this far from the volcano, but there were still signs of scorching, and the undergrowth was completely gone, so the trees themselves might be dead within the next few months if they couldn't get water through the ash.
Karl wasn't certain how porous the newly fallen ash would be, but once they were outside, he realized that the upper layers were all soft black dust, like an upper layer of dirt, and there would likely be things growing here soon enough. If that was the case, the trees would likely be able to grow new roots to survive, even if the ash layer didn't let much water through.