Question about "Natural Disaster" card in "The Cataclysm" scenario: Are wounded units considered to be 'destroyed in combat' for the purposes of dealing damage?

Just wondering if the Uthuk will suffer quite a bit due to this card or if the damage is only taken if the unit is destroyed outright.  Also if the Dwarven Guardian would protect you here.

Just wondering since I still haven't beaten this scenario solo.

I don't have my cards with me, so I can't say for sure based on what "Natural Disaster" says, but from the rules, it looks like wounded units would still count as destroyed during combat since it is the last step of battles/sieges.

I'd say yes - as Budgernaut says, wounded units are destroyed as part of step 5 of the battle phase. Natural Disasters states "when a player's unit is destroyed in combat…", so yeah, the Uthuk will take a pounding. But hopefully, with only 10 strength needed to be rid of the card, it won't be in play long enough to be of much harm (battle being resolved before the event phase and all). But then, this probably assumes a team effort and not a solo one. So, hm.