How famines work

Stormwind is unlike our society, which is based on commerse and run by banks, stock-markets and risk-capitalists. Nor is it industrial, run by industrialists, bureaucrats and factory owners. But it is agricultural, and run primarily on the produce of the land. Not only does the main staple, grain (like in Europe) come from the land but also the primary textiles silk, wool and linen. Almost everthing is either locally produces or very very expensive. And almost every cost is directly proportional to the number of meals that was required to produce this item.
It's an economy run by the producers and not the consumers. Prices are dictated by how long it takes to acquire, not competition.

The very smallest unit is the farmhold, the farmer and his family. They till the earth, raise animals and grow and reap their harvest. This far is things are relatively simple.
However, it is much easier to steal than to grow your own food. This is why there are warriors. Warriors functions to protect the farmer from having his hard-work stolen. However, warriors are very rarely capable of both protecting the land and growing their own food. Hence warrior castes and by extention, nobility.
The very premise of the feudal contract is based on this: "I will allow you to live and raise your family on my land in return for that you spend a reasonable amount of time to serve me". My land in this case refers to the area which the noble has sworn to protect, and serve means to work the noble's fields for a peasant or serve as a warrior for their liege for a noble. This then repeats itself all the way to the top (kings serve the emperor, dukes serve the king, counts serve the dukes, barons serve the counts, non-titled nobility and knights serve the barons and farmers serve the non-titles nobility and the knights. And variations thereupon).

Now, some might argue that Stormwind isn't feudal. And indeed, many evidence suggests that it isn't true feudalism. But on the larger scale I still think that the vast majority of Stormwind's farmers live in arrendation. That is to say they're granted their own little plot of land to feed their family (note: not just the nuclear family. But also grandparents and a small number of farmhands, maids and other servants) with (and sell their surplus) in exchange for working a certain amount of time on the landlord's own fields (or helping maintan his roads and bridges, doing some logging for him or working a mine for him). Then there's a sizeable amount of so called "free men" which are farmers who pay taxes (with the money they get from selling their produce instead) instead of work, but these are unvariable rather rich men. Just a step short of being landlords (that is to say, noble) themselves.

Thus... A farmer produces some food for himself, which will both feed him and his family and (hopefully) a small surplus he will be able to sell, and some for his landlord.

The landlord has a number of farmholds under his suzerainty, because a single one couldn't possibly supply a second family except during extremely bountiful years. Not seldom an entire village (which consists of many farmholds). All in all, like farmholds they will keep some to supply their household (which consists of not only the extended family but also -all- the servants and soldiers serving the house) and the surplus will be divided between the tithe to his liege and a surplus to sell.

Then this system climbs the ladder until it reaches the king. Each step up the ladder the surplus grows almost exponentially. A poor knight might only earn marginally more than a farmer but the king will be able to at leats partially supply an army (and the largest household in the realm, consisting of hundreds of people). SOme of which he'll sell (this is were a vast amount of hard currency comes from, in addition to taxes paid in money as well) and some that will be put in storage for later.

Ultimately... all food will end up in one of five sorts of granaries:
The royal granaries and...
the royal arsenals
The Noble keeps (and the churches' equalient)
The merchant warehouses
And the earth cellars.

The royal granaries store food for emergencies, usually selling off some to the merchants in spring. The royal arsenals store food for the arnies. The noble and church ones do the same role as the royal granaries but for their own fiefs and household forces. The earch cellars is were the farmers keep their own little surpluses.

Which leaves us with the merchants. These men and women do great business in buying up everything from farmers, nobles, church and king sells. Store them in great warehouses and then over the year passes it out in small doses to the shopkeeps who sell it to bakers, butchers, cooks and on the markets.

The crux of the matter is that the harvest happens twice, a small one in early summer and a large one at it's end. The rest of the year you're just living on what was reaped then. This is why winter and mid-spring was not considered to be war seasons, you simply did not have enough food to be able to move your armies safely. By the early summer the warehouses will be almost empty. In poor years the noble and royal granaries as well.

The prices are kept level by the storing and gradual giving out. But if said stores would be insufficient, there'll be nothing to fall back on. It's kind of difficult to grasp in our modern society. But every agricultural society's well being is based on how good the harvest was in late summer. If it is a poor one, then the entire society will suffer for a year. A good one and the entire society will prosper.