I collapsed some of the surface ice two stories down unto some claystone, but it didn't transform into water. I've commenced operations to mine deeper down into the caverns. Also about half my dwarves have become bruised on their whole bodies due to frozen blood and mucus rain. On another note, a blizzard man is out and about but my miner and another peasant can't reach the burrow I've assigned them to because they keep getting scared.
Edit: the peasant tragically died due to an Ice Man-related incident ("The Blizzard Man punches the peasant in the head with its left hand, bruising the muscle, jamming the skull through the brain and tearing apart the brain"), but the miner thankfully made it underground safely. I have one of the other peasants assigned hauling duty to bring some of the butchered parts from the two pack animals I brought with me down into the fort, while the rest cower behind a stone door with me ready to lock it if the Ice Man comes anywhere near. Fortunately, he seems content to wander around the surface getting pelted by flying mucus and goblin blood.
Edit2: We're fucked. I sealed the door when the Blizzard man got near the surface entrance, and after a while I wondered why my mineshaft down to the caverns wasn't being dug. I saw the miner running around on the surface, now being chased by the Blizzard Man. I unsealed the door too late as the miner was soon caught and "jamming the skull through the brain and tearing apart the brain" (he sure likes to do that). The Blizzard Man now has a name "Risepaged". Now all 5 of my dwarves are dehydrated and cramped in a stone room with 2 beds, a few stone pots full of buffalo offal, and 2 plump helmet spawn. Anybody got thoughts on what to do? Even if I successfuly recovered the pick I highly doubt I could plant, harvest, and brew the plump helmets before the dwarves die of thirst. Maybe I could make it to an underground body of water, but even then it would require a pick recovery suicide mission.