If you suspect a deficiency and are unsure about how to fix it, call a roofing contractor. Snow leaks can wreak havoc on a house's interior during the winter - spending a nickel now and save a dime later, as the adage says. Check all areas of caulking. Touch up any suspected deficiencies. Don't use a snow-blower on your roof.
Snow blowers are dangerous and can also tear up the roof.
If you get up on the roof to remove snow with a shovel or similar tool, be careful that you don't damage the roofing materials. Yes, heat tape works but be careful and buy a high quality product. Heat tapes have been known to catch fire and burn down houses. Also be careful about how you install it. You don't want to poke a bunch of holes in your roof.