don't live in California...LOL

Although the key with the plastic cases is to have the bottom one secured to the shelf - they really are quite stable in stack you just want to be sure they don't all slide off.

When my son was very small he tried climbing up a corner cabinet we had and almost got crushed under it. From that time on every cabinet and bookcase in my house has been firmly secured to a wall.

They may look ramshackle but they are very sturdy.