Summer tires are not designed to be used in snow (or cold weather). You might be able to accelerate okay, but stopping and turning will be severely compromised. I've seen an X5 with summer 20" like a sled, sliding down a hill with all 4 wheels locked; luckily no one was in its way.

If you are going to buy a separate set of wheels, might as well make them snow tires, since all-seasons are "no-seasons", the master of no trades.

OT, but given the number of Californians in similar predicaments (1 or 2x a year to snowy Tahoe), I'm surprised no one has done a winter tire loaner programme of some sorts.