What are effective tactics against leveled Magic Anomalies in Skyrim

The problem with the anomalies is that they're fast, move randomly, and they're resistant to many types of damage.

As a sneaky character, I'd probably recommend working the Thieves' Guild quest line up to the end, and using Shadowcloak of Nocturnal or Shadow Warrior (100 Sneak perk) to "cheat" the backstab system. Just crouch right in front of them, and as soon as you turn invisible, mash your attack key. If you get the timing just right, you'll get credit for a backstab, even though you were fully "detected" before crouching. If you've got the dagger backstab damage perk, you can do insane amounts of damage in a single blow.

A few other general thoughts/strategies:

• If you're willing to do the Dark Brotherhood quest line, you can bring Shadowmere to the fight, who is crazy as a tank, moves fast, and can output major damage in a short period of time.
• I seem to remember them being fairly resistant to magic damage, but I did summon my Flame Atronach anyhow, who at least helped a little bit. Her attacks tend to home in, and she can fire from a distance, which can give you an advantage against the fast moving anomalies.
• The Slow Time shout might also come in handy as well.

I am level 46 with level 100 Archery and it was still hard to take them down. My suggestion is use the shout storm call. Storm Call kills them all in less than a sec. Just make sure you don't have a follower, otherwise they will get hit by the lightning and leave your service.

I did the pop in and out strategy at the inn, keeping the avatar alive but not dealing much damage. After doing this for about 5-10 minutes, a dragon showed up to the party and soon thereafter the anomalies were no more.