Sound measures to take in obscure situations (3,7)

I believe the answer is:

fog signals

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'sound measures to take' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.

'obscure situations' is the wordplay.
'obscure' becomes 'fog' (synonyms).
'situations' becomes 'signals' (I can't justify this - if you can you should believe this answer much more).
'fog'+'signals'='FOG SIGNALS'

'in' is the link.

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I've seen this clue in The Globe and Mail.

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