You would do well to adjust the insulation on the knee walls but you also have to place a decent amount of insulation in the ceiling joist area as it looks to be nearly non existent in the pictures. That could save you on your heating bills some but it is not likely to have a significant impact on ice dam formation.
The nature of ice dams forming is due to building heat passing through the roof and melting the snow. Water from the higher warmer parts of the roof runs down to eve area where the roof area is colder and allows the water to freeze. The fact that you have heated living space up to the roof peak (as evidenced by the gable end windows up near the peak) it is likely that the ceiling materials inside are nailed directly to the bottom of the rafters. This leads to minimal insulation in that area allowing the upper roof to be warmed by heat from the upper room.
You should definitely prepare, before snow flies, to invest in a roof rake. Plan to get it now before they get all sold out and are then not obtainable. These things help you to safely scrape the snow buildup off your roof before it has a chance to thaw/freeze and form ice dams. It does require some commitment to ensure that you rake the roof every time that snowfall occurs.
Note that it is best to remove all the snow from the roof to prevent the ice dams. If you just rake the lower edges of the roof and leave the snow up toward the peak that upper snow can still melt and the water run down the roof slope and freeze.
It can be valuable to watch the behavior of your roof after the first light snowfall in cold weather to note where it starts to clear first. If you have a lot of heat leakage on the upper roof it will be very obvious that that part of the roof clears first. Sometimes it is even possible to note where the space between the rafters is warmer.
(Note I used a conventional roof rake when I lived in snow country. I recommend the ones with the plastic rake blade because they are lighter and will potentially do less damage to your roof than a metal one. I have noticed in some Google picture searches that there are new types of roof clearing devices which consist of a long plastic sheet that is pushed up under the roof snow via a specially configured handle. The plastic sheet allows the snow to just slip down the roof. I have never used one of those so cannot vouch if the web site advertising is really as great as they make it sound).
