That bar graph is very good, except it leaves out Great Britain.
https://www.lastationdeski.com/date/fr-calendrier-des-vacances-scolaires-europe.html
Britain also has the weeks of Dec. 30 - Jan. 6 and Feb. 10-17 off, so those are absolutely the two weeks to avoid.
You really think Easter? That's seems late for a long distance plan trip. It's April 1st this season, and April 21st next season. I don't mean you can't have great skiing at Easter, just that it seems iffy for something planned long in advance.
That depends upon the resort. We have quite a few good ones here: Mammoth, Bachelor, Whistler, Banff, several in Colorado. I would stick to Fraser's top 10 list in my previous post, but Val d'Isere and Zermatt are the standouts in the Alps.
As for Easter Week itself, Britain and some other places have that as a holiday, and since the selection of resorts where late season snow is good is much smaller, I would avoid that particular week. My last 3 trips (plus the one set for 2018) have been in the late January/early February time frame just before that February holiday period. This period gives you a shot at a variety of places with a normal or better snowpack and no recent low elevation rain.
In 2019 and perhaps 2020 I plan to try late March/early April, after my Snowbird timeshare but before a late Easter.
You have to remember that, although the bases are much lower in the Alps, the peaks in taller ski areas are at the same elevation as places like Alta and Snowbird. Also, the ski areas in the Alps are much farther north, and the bigger areas have faces pointing in many different directions.
All very true. Whistler is the closest analogy we have here. Its alpine regions are very snow reliable, including into April when 3 of my 6 visits have been. In the Alps as at Whistler it doesn't matter much if the bottom 2,000 vertical is slop if the 3,000 above that is good. The differences?
1) The Whistler alpine averages 400+ inches while most of the Alps at altitude are more like Colorado in the 300 range.
2) Some places in the Alps have Alta/Snowbird altitude at 6-7 degrees farther north latitude, so there are probably sectors in the Alps with elite level preservation of winter snow through April comparable to A-Basin.
3) While the Alps have the potential edge in snow preservation due to altitude/latitude, they seem not to with respect to exposure. The vast majority of areas in western North America have a plurality of north facing terrain, particularly for steep ungroomed. Predominant sunny exposure for steeps in North America is so rare that counterexamples like Jackson stand out like a sore thumb. The Alps have quite a few places like that, notably the Arlberg in my experience.
You can get a feel for exposures using Google Earth, which I have done for a couple of projects. 100 of the top North American ski areas average 42% north exposure and 12% south exposure. A sample of 42 resorts in the Alps average 32% north exposure and 19% south exposure. The bottom line is that the range of snow conditions is inherently much greater in the Alps due to the big verticals and higher proportion of sunny exposures. The groomers have greater skier density over there since 95% of the people stick to them. Conversely the lower density terrain off the pistes may preserve better in the Alps, certainly in terms of powder lasting longer. But the more you range afar from the pistes the more you should consider hiring a guide.
Trails maps usually post altitudes in meters. By March you want to see a lot of terrain over 2,000 meters. Getting into spring make that 2,500 meters. Trail maps in the Alps are not good at all for exposures which are often all over the compass but have to be portrayed in two dimensions on a map. You can play around with Google Earth or consult this for Fraser's overall snow quality assessments:
https://www.weathertoski.co.uk/european-resorts-a-z/