Can she by any chance fiddle with them to get one tornado to cancel out another one spinning the other way?

Tornadoes jump too much and move too fast for this to really work, though the effects are pretty spectacular.

The Nolofinweans have an insulation enchantment for cloth they used to get across the ice. They shared it rather reluctantly, apparently, but now there's that and it allows for slightly better breath masks. Maedhros is in favor of sending Morgoth a bunch of tornados. Curufin thinks that he can come up with a way to modulate the frequencies of the songs to get a directed effect. Everyone's very very worried about the Men, especially with the young children.

Well, she can make a shit ton of healing rocks to compensate for her not being able to literally be everywhere at once. She hopes Curufin gets somewhere. In the meantime she sits on the wall and makes a little progress against the oncoming smoke, what she can confidently handle.

Curufin gets somewhere. He comes out to her with an absurdly complicated diagram - "this is all drawn on things in your wave interference physics books, so thank you for those" - showing how she could do shaped baffles for each songs and different periodicies and frequencies to get the effects to be - well, not unidirectional, but at least "all directions but this one", so smoke could be encouraged to travel around the city.

...Okay. She's going to go test this in the desert with kicked-up sand to make sure she gets it right.

There are no tornadoes and the kicked-up sand mostly moves in the right direction. Only mostly, but better than last time.

She practices a bit, then pops back and gets underway. Time's a-wasting.

It is turbulent and loud and deeply annoying but this can funnel most of the smoke around the city, sort of, after careful placement and some tweaking.

She can keep the sound from getting in at full blast.

And make the smoke invisible, for morale's sake? Though people might not know about it, or the young children might forget, and sneak out - maybe she could turn it swirling gold and silver?

...Yes. She can make the smoke glittery.

Himring is surrounded in glittery smoke. The Elves decide to call this good enough and throw a party.

She will have to touch up the smoke occasionally - she got it all by making it invisible almost as far out as she could see with her enhancement goggles, and re-visibling and glittering it in advancing layers from there - but she can spare a little while to go to the party.

The theme of the party is that Morgoth sucks and is too scared to come out and fight them face to face. This seems like possibly an unwise party theme, but they're quite into it.

Well, is it likely he's going to see it?

No one knows how he gets his information, but no, probably not.

Then this seems like a fine party theme to her.

Everyone is wearing glittery outfits and a lot of jewelry and the dancing is masquerade-themed to accommodate the fact it's still wiser, with most of the smoke diverted, to wear facemasks.

Loki's just spamming healing spells on herself whenever uncomfortable. She'll do her outfit in illusion.

She has pretty much gone through the list of available Quendi girls but there are still certainly lots of dancing partners.

Dancing's fun even when she's not picking anybody up.

Two days after the smoke crawls over their corpses, the orcs get up and start marching on the city again.