Cops allowed to seize firearms even before crime is committed

I'll be super pissed the day the come and take my guns. But I've also been in a situation (at work) where our department had the local sheriffs office confiscate guns from a guys house. He had done nothing wrong, yet, but he was threatening harm to himself. In Florida, we have a law that allows people who are a danger to themselves to be involuntarily hospitalized. But what happens when that guy gets out of the hospital, and is pissed at more people then ever and he has an arsenal at home?!

The guy who we called the sheriffs office on had an arsenal in his house. Automatic weapons, rifles, handguns, shotgun, knives, and thousands upon thousands of rounds of ammunition for each weapon. I know that we probably horribly pissed him off, but I think we probably saved a couple lives that day.