OMG this was my life yesterday... and it didn't even snow. Stupid VA ;) I'm from NJ, so I laugh at our school closings here!!
Best thing to do I've learned, is do a little bit, every hour. I don't know what kind of time constraints are required for your job, but for me, I do a little bit at a time (when I can steal a few minutes away from the kiddos)... I have a VERY naughty 1 year old... and my 7 and 5 year olds can only help but so much.
I get overwhelmed with work when all the kids are around, that's for sure... but spacing out my work day helps. You may end up putting in 10 or 11 hours as opposed to 7 or 8, but it does help. I also put myself in 'time out', tell the kids they can't talk to me or ask for anything because, hey, mom's in time out... then I bust through as many emails as possible!
I also used to work a stay at home job which required me being on the phone 24/7. I worked at home, but my customers thought we were in an office. If the kids were crazy loud in the background, I used to tell my customers that some other client brought THEIR children into the office ;) Ahh, the [lame] tricks of the trade ;)
Good luck, and try not to stress. I even sometimes tell my kids it's nap time... even if they don't nap, they have to take 30 minutes of quiet time, in their room, reading books or doing puzzles. OR if I'm mad, I tell them to clean it up ;) Either way, it keeps them busy, and I can give my work the undivided attention it needs for a little while :)