Too Snow or Not too Snow by Mark at UA 5/1/13

New post on UnofficialAlpine.com

It’s Been A Rough Two Seasons…Looking Ahead To Next Season

by Mark

No, this is not going to be an article about surviving the takeover of Alpine Meadows by Squaw Valley. Let’s talk about snowfall records. If you have not yet heard, we just made it through the second driest season in recorded history in Tahoe. Those records extend back about 130 years between the Central Sierra Snow Lab and the Southern Pacific Railroad. If you think about it, we survived most of the last season on one huge storm cycle in December, and a whole lot of cold temperatures that preserved that snow through early March. The only year that was more dry was 1976-1977 – which was a year that many Tahoe resorts learned about the importance of snowmaking systems. During that season, I spent far more time at Ski Incline than either Alpine Meadows or Squaw Valley.

The odd thing about winter in the Sierra Nevada is that it is difficult to pinpoint “normal” or average snowfall. Although the Central Sierra Snow Lab reports a seasonal average snowfall of 1045 cm (411 in), the variations are huge. The lowest year, 1976-77, produced 450 cm (177in) of snowfall. There have been several years where the total has approached 2100 cm (825 in).

I ran a quick statistical analysis of the data from Donner Summit between 1879 and 2011. It wasn’t perfect as I estimated the snowfall totals from a graph posted atTheStormKing.com. The standard deviation for the data turned out to be a whopping 350 cm. I am stretching pretty far back to my college statistics class here, but essentially that means that any number up to one standard deviation above or below your average could be considered “normal.” Using that as a guideline, “normal” snowfall for Donner Summit ranges between 700 and 1400 cm (275 to 550 in).

If we are really interested in what happens next – we should be looking at the anomalies, or the years outside of that normal range. Looking at the modified graphic below, the green line represents “average” snowfall. The lightly shaded box represents the standard deviations above and below average, or what could be considered “normal” snowfall. Looking at the numbers that fall below that box, we can see that there is truly only one time in recorded weather history that we have had three bad years in a row, starting in 1923.

 

Graphic courtesy of TheStormKing.com

Graphic courtesy of TheStormKing.com

The historical record is really all we have to go by at this point. The Farmer’s Almanac was not written for skiers and snowboarders and the long range weather models for next season won’t begin to take shape until October. The best we can do is answer that question of “Can we have three bad years in a row?” with an answer of “it’s very unlikely.” I’ll be dreaming this summer of another winter like 1952.

 

Winter of 1952

Winter of 1952

Editor’s note: My apologies to Miles Clark at Snowbrains.com. I have had this graphic sitting on my desktop for a few weeks, planning to do this post about a week after the season ended. I saw today that Miles covered this topic, albeit very briefly, in a post today. I figured it was time to get out the calculator, finish the statistics and get you the full report today.

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