Where's da' Powder?
February 4th 2019
**The graphics in this post work much better on a laptop or bigger screen. **
I moved to Colorado in November of 1997- following an old snowboarding friend. I had come out to visit this friend the two years before, probably around February as that's when our winter vacations are back east. I was already solidly addicted to snowboarding but up until that first trip out here, having ridden New England ice my entire life, I was, alas, a park rat. I had never experienced the wonders, and sometimes extreme frustrations, of real powder. My memory of those two trips out to visit him in Vail- which would have been the winters of '95/'96 & '96/'97- are epic. Waist deep snow every day. Dropping cliffs. Goggles and hats flug off me as I gleefully cartwheeled through the powder (this was before helmets).
I was hooked. I declared to my parents that I would be only applying to colleges in Colorado and that I would be taking a year off (at least one) to live in Vail where it snowed a foot every day and everyone was happy.
Move out here I did and I have snowboarded (and now skied) a ton. But a conversation with another powder addict friend this winter sparked a question for me. Since those years visiting it feels like we've never really gotten that kind of snow again. Was it just my imagination of how much snow Colorado got those winters- especially in comparison to New England- or were those truly epic years and I just got unluckly and moved here a year too late?
So that's the impetus for this data adventure. Of course, one question tends to lead to another. What has the snow been like at other mountains? Should I really have moved to Tahoe instead (as another friend and I had contemplated way back then)? Is there a best time of year to go visit various mountains?
It turns out tracking snowpack is a little complicated. So here's the nitty gritty disclaimer. Snow comes in many forms. It comes in Colorado Champaign, and Sierra Cement, and everything in between. What this means is some snow has significantly more water content than other snow. There are as many snow preferences as there are powder addicts so I'll leave that debate to another time. The snow data I collected for this project is called Snow Water Equivalent. It means, if you took the snow that fell and melted it, the SWE is the amount of water you would end up with. Clearly denser snow will have a higher SWE. The way to deal with this from a "powder" perspective is to then look at the density of the snow and calculate the snow depth. Unfortunately, historically, SWE is a much more commonly collected metric than density. For that reason all the data in this post is the raw SWE. I will note, here and there where consideration should be taken for varying density of snow.
First, I think I need to answer the very first question that sparked this research: Were the winters of '95/'96 & '96/'97 in Vail really as epic as I remember?
Snow Water Equivalent for the Years 1987 - 2018
It wasn't just a dream. In fact February of '96 & '97 were some of the best February's on record since this data started
being collected in 1987! I'm not crazy, just unlucky. Or maybe I should consider myself lucky for having been able to come out those
years, even just to visit.
Let's look at the rest of the mountains now. I've collected data from 21 of the largest ski mountains in the west. I'll admit, it's very Colorado heavy- I do live here. The data for all the US mountains was collected from SNOTEL sites near each mountain. A SNOTELsite is a remote snow monitoring station set up by the USDA Natural Resources Conservation Service. The data from the Canadian mountains was collected from a British Colombia government site.
When looking at this chart, remember that some mountains have denser snow than others. The massively high snow totals for Squaw are likely more indicative of their "Sierra Cement". They do report some amazing snow though- like in 2017 when the there was so much snow they had to dig the lifts out.
Now let's look at how the snowfall changes throughout the winter. I was curious to see if one could choose where to ski based on the month.
Are some mountains better early season and others better late season?
Mean Snow Water Equivalent per Month for all Years Reporting
For the most part the mountains look about the same. Clearly some shed snow earlier that others (Eldora, Purgatory).
Others take a bit longer to get going in the fall (Mt Baker, Jackson, Snowbird).
Up next for this data is getting down to the nitty gritty of powder days? Can we quantify a powder day and, if so, are there patterns we can see in their frequency? Do some mountains get more powder days in certain months than others? I've already started looking at the data and it's messy but I think there's something there.
The data for this project was cleaned and arranged using a mixture of Excel and R. With the exception of the static first chart, the two other charts are D3. I tried a number of different chart types for this project. Most notably, I tried a small mulitples Radar chart type for the monthly mean data. While it looked cool, it was not as easily understandable as the small multiples area chart I ended up with. As visualizers this is constant battle- cool looking vs. coherent. Sometimes we get lucky and get both. It was hard to give up on the radar chart as I had spent a lot of time getting it to work and cleaning the data to pacify the D3 beast. But when my husband looked at it and said "I don't get it"-- and then said it again after I explained it to him-- I knew it was a stretch.
All the D3 code for this project (and all my other projects can be found at my bl.ocks page. I try hard to comment them as thoroughly as possible. I believe that not commenting your code and then posting it for others to learn from it is a form of newbee Hazing)