Is there a good raster format for dealing with a large number of NoData cells?

I do a lot of flood modeling and mapping, and recently I've been using rasters to show predicted flood depth and/or elevation for large areas, often for an entire county.

I've just been using the default ESRI binary grid format, but I'm wondering if there might be something more appropriate. These rasters use a huge amount of space (especially at cell sizes of 5-10 ft), and the vast majority of the cells are NoData, so they're just going to waste.