I am writing a short article where I have to describe following situation. Nothing good happens for a long long time, and people are desperate. Then things change and soon go to the opposite extreme, where things become so good that it becomes unmanageable and creates another problem which is not as serious as the earlier one.
For example, an airline company goes several years with few passengers interested in flying with them (drought). Then all of a sudden, things change, demand far exceeds the number of seats available, and the company is overwhelmed dealing with so many bookings (storm).
I cannot use 'drought followed by storm' because of the part highlighted in bold above. The second problem is a "good" problem to have, but the first one is not. We couldn't think of storm and drought that way.
Best Answer
This may not carry precisely the restrictions on meaning that you are after, but it is an umbrella idea over what you seek:
This means that things (good or bad) will happen all at once, once they start happening, perhaps to an overwhelming degree. Your example of the airline is a perfect use case for this expression.
Other possible use cases:
This expression is a fairly new phrasing of an older expression, coined by the Morton Salt Company to publicize the marketing point that when the weather is humid (When it rains...), their salt still flows freely (it pours). http://www.mortonsalt.com/our-history/history-of-the-morton-salt-girl
The original, it never rains but it pours would work also, but is much less common and people might actually try to parse it, instead of just "knowing" the meaning.