A recent cold snap of temperatures between -20C and -28C (-4F and -18F) has caused an ice jam on the Nechako River in Prince George. The town recently declared a Level 1 emergency when the ice jam reached the confluence of the Fraser River. Ice jams cause the river level to rise and can lead to flooding. The last time the river jumped its banks due to an ice jam was back in the winter of 2007-08. The ice in an ice jam is dangerous and unstable and not suitable for walking on.