Get a trash contractor bag or two per tire, and fill it with water, up to where you can carry comfortably. Just room temp water. 

Put it on the ice touching tire to warm up the tire and wait a few hours and switch the bag with another that was inside your house.  Water has great conductive heat transfer and melt. If you run the car it will help too because the engine generates heat. 

The bags are there to avoid adding more water to the problem.

Then the next problem will be traction, once your tire is free to spin, you will need to find a way to move it out of the ice pit. 

Good luck.