I lurk more then I post. But this is something I can help with as a "local"
Natural disasters -
Severe Thunderstorms
Occasional Tornado - The last one we had in Kent County was an F0 about 3 years ago
Very Localized flooding - You have to live close to the river or one of the streams to see flooding.
Winter Storms and Blizzards
Grand Rapids is about 30 miles away from lake michigan, somedays we are spared the worst because we are on the west side of the lake. Some days we have what they call "lake effect" here is an explanation of that.
http://en.wikipedia.org/wiki/Lake_effect_snow GR isn't to bad with the crime rate and depending on where you want to live you can easily get away from the city within a 15 - 20 minute ride.
KenK is right about the economy. Michigan is getting hit pretty hard right now depending on what industry your in. My wife and I have been pretty lucky that we have jobs that haven't been effected by it.
If I can help with anything or answer any questions feel free to let me know and I'll get you my personal email address.
- Jeff (AKA MrEarp)