Combine blueberries, 1/3 cup sugar, and 2 tbsp flour in a small saucepan; cook over medium heat for 5 minutes or until thickened, stirring constantly. Set aside.
Cream butter, gradually add remaining 1 cup sugar, beating well at medium speed of an electric mixer. Add eggs, one at a time, beating well after each addition.
Combine the remaining 2 cups flour, baking powder, and salt; add to the creamed mixture alternately with the sour cream, beginning and ending with flour mixture. Stir in almond extract.
Spoon half of the batter into a heavily greased 10 inch tube pan. Spoon half of the reserved blueberry mixture over the batter. Repeat the procedure with the remaining batter and blueberry mixture. Swirl through the batter with a knife. Sprinkle with pecans. Bake at 350 degrees for 50 minutes. Let cool in pan for 5 minutes. Transfer to a serving plate.
Combine the sifted powdered sugar, 1 tbsp warm water, and 1 tsp almond extract in a small bowl. Stir with a wire whisk until smooth. Drizzle over the warm coffee cake.