Once the cold onshore flow is snow at sea level then the totals can really pile up. We saw the models try to accumulate snow in that scenario last winter but it wasn't realistic.
Definitely not in the grand scheme of things.
Caveat is that (especially north of Roseburg) with our access to low level arctic air we do see much colder historic extremes than the central valley of CA does. Portland and Bellingham have seen single digit maximums before and -15 to -20F minimums have been achieved in the lowlands. Whereas the whole of Bakersfield to Redding has never seen highs below 29 or minimums below 10 in its recorded history.