Was up over this last weekend (Sat/Sun). Anything below 1300m (bottom of Red/Emerald chairs) is pretty marginal. Its been cold enough that they have been blowing snow onto the runs at the lower elevations. So you can ski right down to the village if you wanted to, but you probably wouldnt want to.
From 1300m to 1600m (top of Emerald/Red), coverage is fine. The main trails have decent coverage and some of the off piste is fine as well. We were finding boot deep powder stashes in the trees, however not all of the gladed areas were skiable yet.
1600m to the top is excellant! Lots of pow to be found on 7th Heaven, Harmony bowl, Whistler bowl without even having to look for it. This is 2-3 days after the big dump, which normally unheard of at Whistler. Typically everything usually gets skiied out in 1hr. We had a hoot on Harmony on Sunday. Boot top to shin deep pow. Harmony had been closed most of Sunday and was only open for the last couple hrs. Most ppl had given up waiting for it to open, plus the visibility was pretty poor. We know our way around Harmony bowl pretty well, so fog didnt bother us. The runs we had on Harmony were the highlight of the weekend. The coverage from 1600m to top is great! I guess most of the rain that washed out the lower slopes fell as snow up top.
Going up the gondola, it looked pretty bleak. I was wondering if I had made the right choice bringing my B3's. You would have never expected the kind of great conditions up top based on what you saw below. Even though we could only ski the top half (1300-2300m), that was more than enough vertical for us. That translates to about 3000ft of vertical which is more than a lot of resorts when they are 100% open.
So basically, if you're coming in March. You've got nothing to worry about. There is going to be even more snow between then and now. So conditions will only get better.
I have some pics which I'll try to post later. I didnt take too many up top cuz were having too much fun to stop.