Hi Douglas,
I have sent this before but it seems not to have been merged with this post. We have SMs in some of the most wet and windy locations and the radios fill up with water. It is resolved by drilling drain holes in the radio to allow the water to clear. The case distorts in rapid cold front events, letting the water in, possibly by capillary action and there is no exit bar evaporation. An another hole at the front of the radio to release the water from the reflector area. When dismounting these radios the water just poured out having had the PC board and components submersed.
Russ.
If it is under warranty, send it back! Make sure you send pictures of it mounted and how the cable makes at least a 16" vertical into the radio (prevents water source being the cable issues).
Forced water ingress can happen along the bottom vents but unfortunately there is no provision for its egress. The seal along the body is actually fairly good however it is not perfect due to the housing being plastic and not rigid enough. If you take the radio apart and apply silicone grease (dielectric grease) to the runner where the seal sits (both sides) then add the seal, it will not allow water in as the grease acts as a flexible, dynamic seal that does not wash away. Silicone rubber (RTV) will not do this as once it sets it fills the void but will not move with the changes in the plastic.
We are in roughly the mid-west (Saskatchewan) near the Montanna border, and we get both weather extremes (+108F to -45F) with monsoon type rains (drops 4" of water in 20mins!)
with winds that are commonly in the gale force levels but have not had the water problems that you have. We also learned the hard way to make sure that we add silicone grease to the seal.
For your radios that are out of warranty, they should be mostly recoverable even if submersed if you replace the corroded components and soak the boards in 99.9% isopropyl for 10sec then let them dry for a week before you power them. Other than the connector everything is a sealed component, so ingress does not usually happen.