I agree that we don't even need a volcanic eruption, just a chain of unfortunate events. A late spring frost that killed half the crops (is that the "back-winter"? We call it "freezeover" in Russian
). A hailstorm just before harvest that brought down the other half. The winter started early - the ground froze deep before the snow fell, (which would reflect on the success of next spring's crops), and any late crops were lost. Then, a couple/few weeks later, there was a series of large snowstorms that effectively buried the residents of the Mead Hall and isolated them from the rest of the world, as the roads became unpassable (such events happen here almost every winter - we have freezing temperatures way before snow, and then all of a sudden the snow banks become quite high in a matter of a week). Perhaps we could talk about men trying to brave the roads to bring food from elsewhere, but no wagons could be brought in the snow (dogsleds not invented in Rohan yet?), so the results were minimal. Firewood could also be an issue; I don't remember the exact layout of the land around the Hall, but wasn't the wood bit farther away than is convenient? Also, the local lords would be heavily involved; from what I gather, any grain that the Hall has would have been collected as taxes from the lords, right? The hall itself doesn't do farming. The lords' people also suffered, and the lords could be blaming the Eorl for stealing their food and not helping [enough] during a time when his help was needed.