Jetboat grounded as Shotover freezes

Stuff NZ
"The worst big freeze in almost 20 years has left parts of the Shotover River frozen solid, metres across, keeping jetboat operators off the water for almost record periods. The river has been choked with ice, making it too dangerous for boats to operate because of the risk of large chunks of ice getting sucked into the jet units, causing power and steering to fail. Ngai Tahu Tourism southern region jetboating manager Clark Scott said until 2pm yesterday Shotover Jet was getting close to its 1994 record of 11 consecutive days not operating because of ice. The big red boats finally got back on the water for two hours after a frustrating eight-day hiatus. ......MetService was forecasting another -4 degrees Celsius overnight chiller last night and possibly again tonight. Mr Scott said one morning last week, when the air temperature dropped to -10C, the water temperature was -2C even though the entire river had not frozen over. "It's because the water is flowing so quickly it has no chance to solidify. It's phenomenal."