Combine sour cream, mayonnaise, lemon juice, dill and garlic powder in a small bowl. Cover and refrigerate for 30 minutes, or until ready to serve.
In a small bowl, combine the flour and baking powder.
Pour the salmon, with the juice from the can, into a medium bowl. Using a fork, break up the salmon and remove any bones. Stir in the eggs, green onions, and salt and pepper to taste. Slowly stir in the flour mixture.
In a large cast-iron skillet, heat about ½ inch of oil to 350 degrees F.
Take 2 to 3 tablespoons of the mixture and place it in the skillet. Slightly mash down to create about a 2 ½ -inch wide patty. Add a few at a time to the skillet and fry for 2 to 3 minutes per side, or until golden brown. Let cool slightly on a paper towel or wire rack. Serve with the dill sauce.