After any heavy downpours of rain we have, you are more likely to encounter a washout in a bunker. If so, how do I get out of it?
If your ball lands in a bunker, the nearest point of relief is outside the bunker. So, can I drop free of penalty outside the bunker?
Good try! To obtain relief from a washout in the bunker, you must determine the nearest point of relief IN the BUNKER, no nearer the hole and drop within one club length of that point in the bunker. 
In this image, both right and left hand golfers could obtain relief if your ball is at A.
However, at point B, only right handers are affected by the washout (rule 25 says: “interference occurs when a ball lies in or touches the condition or when the condition interferes with the player’s stance or his intended area of swing”).
Bad luck Gary - there is no interference by the washout for left handers. Play it as it lies!
Now, is there any way I can drop out of this bunker when the washout causes interference? Yes - rule 25 goes on to say that in a bunker the player can lift the ball and drop the ball, “under penalty of one stroke outside the bunker keeping the point where the ball lay directly between the hole and the spot on which the ball is dropped, with no limit to how far behind the bunker the ball may be dropped.”
The same rule can be applied if your ball lies in casual water in the bunker, which is also classified as ‘abnormal ground conditions’!