"Neither snow nor rain nor heat nor gloom of night stays these couriers from the swift completion of their appointed rounds"
-- inscription above the James Farley Post Office in New York, derived from Herodutus, circa 500 B.C.
Doesn't say anything about 80 mph winds, though.
The severe winds happening in Centerville, Utah, have closed the schools, knocked over semi trucks and trees, and produced this message (via Twitter) from city officials: "Postmaster has cancelled mail deilvery today 12/1."
(And, for the record, the above quote is not an official oath or creed of the United States Postal Service. The post office has no such thing.)