I thought that triangle was permanent over SW San Juans...till maybe March.
Not really. Colorado, including the San Juans, spends a
huge % of the season at Considerable (stage 3), but not a lot of time at High 4 or Extreme 5.
tseeb, for the Sierras I note two unusual items in this years current 2nd place (though non-'official' old RR records indicate multiple years of snowfall similar to or potentially more than the 1951-52 record year). One is that many storms have been colder than typical(note 1), so much more snowfall at lake level in Tahoe/Mammoth town to be dealt with for example. Also, that it has been mostly very consistent - eg every month is a huge snow month, not a ton of long gaps between storms which a bit unusual for the Sierra, IMO.
Finally, If I recall, some of the big snows in official record years had much of it in late March-early May... Which means that earlier in the season snowfalls were already melting prior and the big new late season snowfalls also melted out (at least partially) much quicker leaving much less human impact on roads, structures, shoveling, etc... than this year has provided.
Note 1: I find it hilarious when various YouTube video creators dealing with the snow in the Sierra start off by talking about how "cold it is this morning" then reference temps that are only in the mid-teens. Such a banana belt of skiing, lol.