21 across: Setter is crazy to retreat, grabbing spades for disaster (7)
This could be brilliant, but the two explanations put forward seem to me to be lacking something.
My own incomplete explanation, which is not the greatest, goes like this: setter is crazy = nuts am i, which somehow becomes tsunami.
A far better approach put forward by Timbo is the following: setter is crazy to retreat, grabbing spades = I’m a nut to retreat grabbing spades = tunami grabbing s = tsunami = disaster.
The reason I’m not completely happy with the Timbo explanation is the plural form of spades. Shouldn’t spades mean that two esses are inserted into tunami? Is that a valid criticism? Or am I — perhaps we — missing something?