Why did the 2013 Multnomah County property taxes go up so much?

My property taxes have gone up 10.5% this year – a huge jump over 2012. The big reason your property taxes went up is due to three bond measures that passed recently: Schools, Libraries, and Green space. Taxes also went up due to property values rising and the fairly predictable 3% annual increase.

The Oregonian has a great article on Property Taxes in Portland, Oregon in 2013

How do I appeal my property taxes in Multnomah County? Info and forms here.