I just bought a house in northern Midwest where there's lots of snow and was planning on adding blown in cellulose insulation to attic space. Then I noticed that there are no soffit vents in the main portion on the house. House has two scissor trusses in the middle and only at the lower end of each end of the house are there these soffit vents. At the one end is a garage and a knee wall so these soffits are cut off from the main house.
I'm looking for recommendations on whether I should get proper venting before insulating with 16" of cellulose. House has been updated over the years but has been in this shape for at least 10-15 years.