Another way that a drought is bad

I have a cob oven in my back yard and when I went to light a fire recently I noticed a missing brick near the back but upon further inspection I found that the floor had collapsed beneath the bricks. The drought of this past summer/autumn had caused a crack to open up near the back of the oven and I figure the crushed rock and gravel had shifted and caused a sink hole in the sand bed under the bricks.

This had happened at the doorway too and it needed about 15 kg of sand to fill in, but this other hole looks like about double that. My camera is on the fritz so I can't post a picture yet.

So I'm thinking a nice lime layer under my next oven or maybe go all out and build a brick oven :) And there is new by laws concerning wood burning stoves to consider too.