The back and forth in the global warming debate about snow coverage is always amusing. The debate has stated both that snow will increase or decrease because of global warming. Both news stories get coverage almost simultaneously because every year there are some places that get more snow than average, while others get less than average. All a person needs to do is Google global warming, snow and let the conflicting stories and news articles paint the funny picture.
What I always do is simply show the data and my analysis of the data. The source for the data is the Rutgers Snow Lab. I focus on the data that is available from 1972 which means that 40 years of records will be available at the end of this year. Of course that is only a blink of an eye on the geological scale, but that is what is available. Here is what the weekly data shows for 2011.
Certainly the average trend for the year was followed as one would expect. The late-spring to mid-summer region was lower than average, but the snow coverage rebounded on time and even faster than average for the NH as a whole. There were regions that had less than average, but that was more than made up for in the regions that had excess snow.
This can be seen in the November 2011 “departure” graphic of the NH.
This really highlights one problem that people have understanding the Earth’s climate. I was in an area that experienced more snow in the Spring, but less in the Fall. Perceptions are formed by what people experience, unless they look at the data. In the global sense the year was normal, but many regions experienced unusual snow coverage, that is also normal.
The average snow coverage for a year in the NH is 24.9 million km2 of snow. 2011 was almost normal at 24.7 million km2 of snow. So while it was slightly below average, it was only -0.24 standard deviations from average which means it was statistically normal.
A linear regression would show a slight downward trend in the snow coverage, but that doesn’t have a lot of meaning. I will get more into that in the next article on the snow coverage later this week, but for now I will leave you with the weekly snow coverage for the past 39 years.
This is far more valuable than the yearly average and I will break it down into more detail in the next article. One thing it does show is that there is no reason to believe that winter snow is going to stop any time soon as the NH is still getting >45 million km2 of snow coverage each year. That is a lot of snow.