Regarding the Pipeline Protests, it is more than reasonable for police to use water water cannons in freezing weather. It seems no matter what the condition, people feel police should not ever use force. In this case what would people consider reasonable? Handing out heating pads? If you want to protest be prepared to face the consequences.
Police have spend countless hours and dollars telling the protesters to leave. The protesters are trespassing and they are trying to shut down lawful business. Police have tried everything else. Any other use of force that they could do would take more time and would create more risk. This is the best available option.
No, the use of water cannons in freezing weather is not reasonable. It is a violent act intended to cause great harm or potentially death to individuals. It is an outrageous act and warrants investigation, suspension, and potentially firing of those involved. It should be treated in a similar manner to police shootings.
They say these are non-lethal weapons, but a water cannon in freezing weather is lethal. Using concussion grenades with tear gas can be lethal. Many protesters were doused with water in below-freezing temperatures. At 25 degrees Fahrenheit air temperature, as it was near Standing Rock on Sunday, frostbite can set in within 30 minutes. Even being in water under 50 degrees Fahrenheit can cause exhaustion or unconsciousness in 30-60 minutes.