Recently had this happen twice while snorkeling during a surface interval. I get water in my mask and subsequently in my nose. Seemed like I was getting water in my ears as well. Get back to the boat and end up with a major nasal drip (if it was blood they would be getting everybody out of the water!). No problems like this during dives. Only thing I can think of is I do wear a light mustache. Again no problems during dives so I'm thinking pressure is keeping that mask better against my face than with snorkeling. Now I don't want any part of snorkeling. Not quite ready to shave the 'stache.