A water gun is the LAST thing you want to do...With the frigid temps, the water will simply freeze on contact, compounding your problem.
I'm actually surprised you don;t have signal. The snow to water ratio with these extremely low temps is perhaps in the 15:1 or even 20:1 range,. the snow is powdery. Usually this type of snow does not block the signal.
Must have a coating of ice beneath the snow. Until you can get the antenna cleared of snow and ice, you're out of luck.
A water GUN "Super Soaker" Type Is Good as LONG as you don't use water LOL! - use winsheild washer fluid -that is for winter use.