Global warming is heating up their environments and melting away their glacier habitat. If their home ever got completely rid of ice they'd die of a heat stroke.
There are multiple factors that influence the amount of water that flows in a river.
1. A factor upstream like rain can cause the water level downstream to rise for a short period in time.
2. A blockage in a runoff stream can cause the main rivers water level to rise due to the lack of available runoff path for the water to take.
3. Also the melting of snow can cause the water level to rise as well.
