I like the general idea with some variation.
I think the concept of tier increasing with windstorms is pretty solid. It does the job of discouraging venturing into those areas, and especially if the tier gets higher and higher as you go, I think the effect is good.
What I would like to see more of is the wind flinging you about randomly. Gusts of wind could come and pick you up, or throw you violently against the landscape. It would be extra cool if it did the same to the enemies. You'd lose health from falling damage, or from being knocked against something. This is a more organic mechanic of health reduction than just having decreasing health. The way I picture moving against a windstorm, is that you're trudging through a violent storm, and at any opportunity you duck into a house or cave to rest up or just 'fortify your position'.
This is also how I'd like the windshield placement to play out. There would be little houses and caves you could duck into for a minute, and then you'd go on. The key is, you'd want to have a way to visualize a huge gust of wind approaching, and ducking into a house should cause time to move forward somewhat. So maybe it'll be easier to do (programming wise) if you make little shelters where you can hide from the wind in the same chunk. Miss a few giant gusts of wind and you'll be down to your last bit of health.
I don't think you need any bosses in this type of mission -- they just don't belong there thematically. This should literally be a struggle against the environment with the wind as your enemy. And the more helpless enemies you see flailing about in the wind (possibly hitting you for damage as they fly), the cooler this mission/area type will be.
It could actually be an attraction to go to different area types and see how different native enemies are thrown about in the wind helplessly. It would really convey the idea that this wind is DANGEROUS -- so dangerous that the critters of this world are helpless against it.