DULUTH, MN (KDAL) - Since the snow started piling up on Monday night, Duluth City plow operators have been working 16 hour shifts to try and keep up with the storm that dumped up to 29 inches of snow in some parts of the city. Plows focused on keep the main streets clear and then went to work on the residential streets. As of Thursday 98 percent of the streets were finished and the alleys should be complete later on Friday. To help snow plow operators in finishing work in the coming days, the public is reminded of the change-over for alternate side parking on Sunday. Cars must be moved to the odd side of the street between 4 p-m and 8 p-m Sunday. All 22 plow trucks and 22 graders were called into service to work the storm and over 37 employees have been working various shifts to keep the snow removal equipment on the streets through the week. The snow removal has cost the city about 150 thousand dollars in equipment, sand-salt and staff time so far.