Hi Wilecoyote,
I have a small cabin with 800 watts of solar that is in a similar climate. Can be very cold for extended periods. I stuck with AGM (lead acid) for the cabin, and we have a panel mount that can be put vertical to shed snow.
I have lithium at home, but personally I don't think it is there yet for very cold climates with very low amounts of sun. Like you see, you can chase your tail trying to keep the batteries warm instead of powering loads. There are ways to do it, but they are expensive vs. lead acid in my opinion.