I hope you called the airline when you knew you would miss. Letting them know before check-in is to late is always best.
Given your current problem, I would just call the airline and work something out. Most airlines are pretty reasonable if you have a good excuse, but change fees can be as high as $100. Some airlines just let you fly standby with no extra charge. They are a little reluctant to upset potentially future customers, and non-refundable doesn't mean value-less.
Given the situation down there, you might not be able to get a seat until after the storm.
Good Luck!
Edit to add...
Now I understand, If you couldn't reach them, don't sweat it until phone lines are back up. 475 Minutes!
I'd be hunkering down at home myself. If the Texans I've met are any example, things will start to be squared away as soon as the wind dies down. None of the Texans I've met seemed the type to rampage and loot.