system
Given the following post, respond as if you're commenting on Reddit:
human
[ASOIAF] How do the people of Westros store food stuff during particularly long winters?
gpt
The same way food has always been stored for the long term. Drying and/or heavily salting meat. Or just keeping large herds around for regular slaughter. Fishing through the ice is also a possibility. Since animals in westeros aren't extinct even through extreme winters, humans can still hunt now and then as well. (It's likely that they spend more time than in the real world drying/packaging foods and have much bigger storehouses than we do. There's probably a gigantic agricultural industry we just don't see because it's boring and has little to do with politics or wars.)

For crops and plants, drying is still a possibility. As well as growing foods that take a very long time to spoil, like root vegetables and grains. Some plants can also be grown in primitive greenhouses or in manmade shelters to keep people fed some meager amounts for a very long time. 

And on top of it all, we know the more southern areas of Westeros are more temparate, so they probably are able to grow food even in the middle of winter. It's likely not as healthy or nutritious as summer-grown crops, but they can still grow it and transport huge quantities up north for a good profit.