You realize that every time we deal with one of these blizzards our people suffer on mass even if they aren't starving?i'm not sure.
There must be a limit to Sombra's blizzard powers, and our farming innovations mitigated much of the damage.
Unless we reach the point famine is inevitable (and with Neighpon's import and some new innovation i think it's unlikely) i say to wait, and continue to improve our army/tech and launch our sabotage actions. Sombra seems like the impatient type, if we don't attack in a year or two he'll probably attack us. And then we launch the counter-attack.
We thought he reached his limit last time when he was only able to do slight damage and then we failed a hazard roll now we has surpassed that. It looks to me like every turn we wait is just wait for more rolls to fail and hurt us. What more could we possibly do to improve our forces? we have all the nations in the world we know of united against him? At this point why wait when we know he is making improvements to his force we managed to slow with damage to the mine but he is rebuilding them. Waiting only lets him get stronger.
You are basically quoting the sunken cost fallacy there, an investment of resource doesn't automatically make something the best plan.And how would he do that? The further away from his kingdom he wants to spread the Windigos' frost, the harder it gets. We had to roll an 18 for him to succeed with half our empire. We'd need to roll even worse for him to expand the effect all the way.
After we invested five military actions and 2500 gold into the Peregrine line, we've basically committed to actually use it.
For reference, instead of the fortifications we could have built 50 cannons. That's how much attack power we'd be missing if we discard our plan to let him strike first and invade once his army has destroyed itself on our defenses.
If you want to trigger the East sooner, you could suggest an intrigue action to irritate him into attacking before he's ready.
Going on the offensive would cost thousands of lives, need him to make the first move.
Just because you don't end up using a weapon doesn't make it a waste. It was a good precaution we ended up not needing nothing more that part of military strategy sometime you invest resource in assets you don't use in order to prevent worse scenarios. You don't build walls because you want people to attack you build wall to discourage people to attack. The Line has served its purpose well in that regard.