Uhhh ... it wouldn't happen to be freezing temps there now would it?

If so, might want to check the oil separator. Do a search on it and the "cheese". Look under the oil cap or on the dipstick for the cheese. Frozen condensate can block the oil separator and oil will come out through the valve covers and/or dipstick. The oil separator hoses may be bad too. Condensate can collect in the separator if you do short trips in cold weather (doesn't allow enough time to dissipate the moisture). Then it freezes and clogs the passage ways.

Not trying to scare you but a good precaution to check it out.