Maybe related or can point you in the right direction. I recently visited an area resort on Cape Cod where a golf course was being renovated. On a tour of the facility I asked why there was so much sand being put down and where the loam or topsil was. They put down atleast 8" of a 80% sand and 20% seed mix...and no loam or soil! Pretty sure it was rolled out. They were planting bent grass (tee boxes, fairways, greens) and bluegrass on the first cut. True they have drainage and irrigation, but I was surprised they were using a mix with primarily sand.

If you can pull some of the grass out and take pictures against a white background, with something to show the size (like a coin or something) somebody may be able to ID the grass. It helps to have the roots and if there are any seed heads, include those. In southwest BC, you're in the part that gets a lot of rain and has mild winters, right? Does the grass fill in the bare patches when it dies in the winter? I'm going to guess that you've probably got mostly perennial rye. It won't fill in the bare patches, so if what you've got spreads, I'm wrong about that. But perennial rye is used a lot in places like Seattle because KBG (which is common in most of the cool season grass regions) is too susceptible to fungus in rainy areas. The shady mix is probably a fine fescue mix. One of the fine fescues (creeping red fescue) will spread a little to fill in bare spots. The fine fescue has much finer blades than perennial rye (or just about any other turf grass, really), so you can probably pick it out if you look closely. Somebody walking past the lawn probably wouldn't notice. If it's perennial rye that is getting killed by the snow, you'll need to reseed. Fortunately, it germinates very quickly so you can just overseed whenever you have a problem.

I'm not very good at identifying grass, but it looks like a mixture of KBG and tall fescue. It also looks like you need to sharpen your blade. Some of the grass looks like it is shredding. Tall fescue is particularly sensitive to dull blades and can almost tear more than cut.

Unfortunately I am not able to determine the grass type from that link because the grass is so small, I cannot see the characteristics listed in the link. The only thing I could determine is that the leaf blade tip shape is pointed and that it has stolons on the weird grass. I don't have a microscope to see the rest of the characteristics. Anyone else have some ideas to share?