Frozen milk and power outages

snicksnack

Anyone able to preserve frozen milk in a power outage, and if so please share your tips.  I have over 200 ounces in my freezer and with the threat of Sandy I am freaking out.  This summer we lost power for 4 days, we were not home, but my parents came over and said on day two it was starting to thaw so they trashed over 40 ounces.  I have so much due to work trips and some medical issues that causes me to have to pump and dump for tests. 

I also was wondering at what point does the 24 hour countdown start when it is thawed or if it is starting to thaw?  My mom said she trashed some packs that were frozen but had a small amount of slush in the bottom.   

Finally how long does dry ice stay cold?  I am debating on seeing if I can purchase some before the storm but I am not sure if it is worth it if it does not stay cold long, given I would be buying it a couple of days before the storm.  Thanks