A druid with goodberry
And a 5th level druid with goodberry could sustain 90 people a day if they used all their spell slots.
Still keeping the animals warm and the crops running would be difficult. Although ome can always assume perhaps some level of divine intervention to save the plot/day.
They dont have crops. Its the Arctic.
And like Inuit peeps have lived in similar conditions for centuries without magic. Pretty sure the locals could manage for 2 years.