I would say this is AS dangerous as Yellowstone, considering if it blew, it would completely wipe out the agricultural potential of California, and that would affect everyone, as they are a top producer of goods.

Love skiing there in the winter months, as its one of the best ski destinations in the US, and accessible, but I always remeber the constant little quakes you feel when you are there.

Also if you are driving up from So-Cal...going through that valley, and seeing all the volcanic rock, and obvious tectonic made structures...makes you feel pretty uneasy, becuase its so in your face how crazy it was there at one point in history. Not somewhere you'd want to be for sure. Devil's postpile is a cool landmark to visit, as are the hot springs in the area, but it is what it is.

Be there at your own risk.