Like was mentioned below snow will build up in the root of the sprocket and increase tension on the track chain as the snow packs in and builds up on the sprocket.
I believe its possible that once the pin/bushing is up far enough out of the sprocket root, you could get slippage from it, and of course, when things get tight, you cold break something, as well as accelerate wear.
Tension on a track that has carrier rollers, for the older caterpillars, (R2 I belive does not have carrier rollers) is usually correct when you can pry up on the chain and see 1 1/2" + or - gap, not sure on those without carrier rollers, your manuals should cover that.
You should brush up on undercarriage measuring, to determine the wear on the pins/bushings and or stretch, you need to measure across the pins while they are level and taut. Doing this will help assess the wear and potentially aid in figuring out any repairs that may be feasible to perform to bring the U/C back within spec's. If worn but still a long ways from destruction, or completely worn out, limited use and hours should be ok. Sometimes you can build up the rails, (bottom side of track links, re-grouser the pads or similar) for the desired effect, say getting some tension back on the chain or better traction, it used to be common to build up rollers too, turn pins and bushings to the unused side. Worn rails are easy to spot, check to see if the bottom roller flanges are hitting the pin bosses and making a flat spot, once the rails are built up or new track chain installed, it will stop doing that, also is a bumpy ride when they hit. Some would cut off the flanges on the rollers, run to destruction before replacing the U/C. You won't know the U/C condition until you measure, very possible it could be worn with 20-30% left, a well worn U/C with a lot of part time use left or you may find that some parts are worn more than others or maybe the tractor did not get wore out, had U/C work kept up or how many other scenarios. Its good to measure, as you may determine that say building up the rails is feasible, turning pins/bushings, as well which could get hundreds if not more hours, vs leaving as is and often times when something is well worn or a condition exists with wear that can accelerate more wear, meaning the repairs will prevent that acceleration, and the U/C is back to normal wear rates. Loose tracks, too much tension, abrasive soils, and lots of other things can accelerate wear. Sometimes you can measure up and determine its feasible to run until destruction, then replace, I ran a D8K like that once, ran it on a scraper job, pushing the pans (scrapers) and when it went to the CAT U/C shop, the pieces falling off left a trail and the UAW yard man refused to unload it, being a union shop you unhook the detachable and they operate the tractor in their yard, this time I had to do it and run it right to the shop door, the trail of broken metal reminded me of an old Munsters episode where grandpas hotrod, left parts all over the street.
More than likely just the snow, but it won't hurt to measure your track components and see what you have. You would need to know what the "new" specs were for the R2, then compare measurements, do the math to figure percentage, relatively easy to do. Caterpillar used to offer track gauges, just one piece tool with cut outs to mate up to the parts, that you can easily see how much is worn, as the gauge is made with the new spec's or dimensions. Hopefully some help and not too redundant LOL !