After the ice storm we had now my central heat will not come on. The emergency heat will work, however the outside condensing fan will not come on in heat mode or cool mode. What can the problem be?

You have a split system heat pump I am guessing. First off, is there any sound at all coming out of the outside unit? (you should still hear the compressor turn on)
If so, it could be these possible issues. 1: bad fan motor or bad capacitor 2: defrost relay is stuck causing unit to run in "a/c" mode with fan off.
If this is the case you may need a licensed technician to repair.

Hope this helps.

With the thermostat set to emergency heat, the outdoor unit should not run at all. With a call for regular heat, does the compressor run? You might have to be quick to get outside in enough time to hear it before it shuts off due to high or low pressure with the fan not running.