I heard a warning in Japanese that sounds like "ozo keihou" but what is it?

It was over the neighborhood loudspeaker, and it wasn't "boufuu keiho" or "harou keiho." I know heiho is alarm or warning, but I can't understand the first part of this one. I'm near the water, and it isn't stormy. Can you guess what it might be, or is there a list of common warnings somewhere? I couldn't find anything in the dictionary, but I imagine I'm mishearing it.

2012-10-22T00:09:22Z

I'm pretty sure about the second syllable...zo, or maybe so, but the first syllable I'm less sure about. Maybe bouzo, hozou, ozou, or something like that. I'm pretty sure it wasn't ooame, though I appreciate any and all suggestions. We do get a lot of marine warnings where I am, which don't necessarily affect anyone who isn't going out in a boat. I've extended the question a little to see if I get a chance to hear this again. I've heard it before, but can never quite catch it.

wind-sky-wind2012-10-19T17:33:22Z

Favorite Answer

大雨警報 ooame keiho
大雨 (ooame) is "heavy rain."

洪水警報 kouzui keiho
洪水 (kouzui) is "flood."

In many cases, both are announced at the same time, like:
大雨・洪水警報 ooame-kouzui keiho