Bike options for winter commuting in the mountains I live in the mountains of Vermont and bike 3 seasons a year on my trusty cyclocross bike. This year, I'd like to commute year round, through winter. My commute involves some steep, 10-18% climbs on dirt, gravel, and pavement with icy and/or unplowed snow. I've been debating about trying 2 different winter commuting setups:


Winterize my current cyclocross bike. This option has the obvious advantage in that it's cheap, since I already own the bike. I was thinking about swapping out my Schwalbe Racing Ralphs (700×33c) and going with the widest possible tires I can fit, probably 700x40 with studs.
Buy a fat bike. I've seen a lot of people talking about how much fun a fat bike is in the winter and how good they are for commuting. My main concern is the weight and climbing ability of these monsters on steep winter ascents/descents. Does this seem like a good option for my commute? I like this option because I could keep cycling through the winter, but this also involves buying a whole new bike.


Any opinions/experience is much appreciated. Thanks!

More specifics

My commute is 7 miles with ~2300 feet of elevation change. There are two short, but steep climbs with rolling hills interspersed throughout the rest of the ride. I'm mostly worried about the steep morning descents in bad weather and trying decide which bike option would give me the stability I need. Hauling a heavy fat bike up the hills is less of a concern, but climbing weight is still important to me.
Here are the things I believe you should be considering when making the decision.  

Fat bikes climb just fine.  Yes, a road bike will climb a paved hill more efficiently than a mountain bike under the same conditions.  But, a mountain bike will also climb a muddy single track that a road bike would simply fail to move at all on.  Efficiency and utility are trade offs in this respect.  

A cyclocross bike will be more efficient in many conditions.  However, at some point your cross bike will become unrideable (too much/deep/wet snow) and a fat bike will plod on.  Depending on your weather and commitment to riding, a couple days a year where you shelve your cross bike and take other transportation may be acceptable for you.  However, if you want to make sure you can ride as often as possible, a fat bike will offer you more commuting days.  A fat bike also offers an advantage in this area as far as not finding out halfway into your commute that you are going to be pushing your cross bike the last 3 miles.  It's slower, but a bit more honey badger.

As far as safety, I'd much prefer to descend with ANY snow on a fat bike than a cross bike.  Thinner tires may cut through snow for traction, but when descending that sinking has a tendency to yank the front wheel all over the place.  A wider front tire will float and may have a tendency to wash, but not dig and turn.  

A fat bike would open up new options to you for winter trail riding.  A cross bike just doesn't even enter into this equation.  However, if you aren't into trail riding, it isn't really an advantage to you.  Personally I enjoy winter trail riding above all other forms of riding and I live in the right place for it, so fat bikes are THE bike for me.