There’s still a lot of snow on the ground and with cold and dry weather most of this week, there won’t be a lot of melting, but some of the snow is still going to disappear, even at subzero temperatures.

By now nearly everyone knows the statistics. Since the 23rd of January more snow has fallen than would typically be had in an entire winter. Most areas have seen 80 or more inches of snow this season, at least that’s what’s in the record books. But if that much snow has fallen, where is it all? You may answer that it’s in your backyard, but seriously, where did all that snow go?

Temperatures have been below freezing 22 days since January 23rd. In February alone, Portland has had over 32 inches of snow and nearly the entire time the temperature has been below 32F. Depending on where you live, most areas have between 20 and 40 inches of snow on the ground. Some of the greatest amounts snow today exist across parts of Oxford County and coastal York County.

So where has 40, 50 or even 60 inches of snow gone? How long will it take the rest of the snow to melt? Here are some thoughts on why there isn’t more snow on the ground right now and when we might see the grass again.

Sublimation
You might not realize it but snow, which is a solid, can change phases and become a gas, or disappear without ever becoming a liquid. The process, called sublimation, occurs when any solid object goes directly into a gas. Things like mothballs and dry ice can also sublimate over time. The ice cubes in your freezer sublimate, this is why they shrink in the tray. The snow on the ground is sublimating and therefore the depth is decreasing.

Melting
Even though it’s been so cold, some snow has melted. As the sun’s angle gets higher in the sky, the increased solar radiation helps to melt the snow. Even when it’s below freezing some snow will melt on south facing areas as well as on the darker surfaces like pavement. You’ll even notice snow melting around tree trunks which are darker and absorb more heat.

How We Measure
If this winter had occurred 40 years ago, the amount of snow measured in each storm would have been less and therefore Portland would not have had nearly 90 inches of snow right now. You might think this is ridiculous. Isn’t a foot of snow in 1965 the same as foot of snow in 2015? The answer is no.

Decades ago snow was measured differently. Today, we have snow boards. According the National Weather Service, “A snowboard should be any lightly colored board that is about 2 feet by 2 feet. A piece of plywood painted white works very well. Ideally, it should be painted white to minimize heating by sunlight.” These boards are used to measure the snow that falls. They are measured and cleared every 6 hours or 4 times each day. The measurements are then added up and that’s the total amount of snow for a storm. Here’s the problem. This eliminates a percentage of compaction that occurs during snowstorms. This creates inflated snow amounts as compared to older records. It’s not that our snow amounts today are wrong; it’s just that they can’t be compared to earlier storms or years.

Compaction
As snow falls on top of itself it compacts and as I just mentioned, you can remove some of this effect by measuring snow more frequently. If we measured snow every hour by clearing the snow board the amounts would be even higher, especially in storms with denser snow. Another reason you don’t see 6 or 7 feet of snow on the ground is due to the natural compaction occurring during a storm and in the days thereafter.

When Will We See The Ground Again?
I can’t predict exactly when the ground will be exposed, but I don’t think spring sports are going to have to be cancelled and here’s why. One thing that is predictable is the strength of the sun. No matter how much more snow we get between now and May, the sun will win.

Back in March 1993 there was a foot of snow on the ground to start the month. After several storms this number increased and by the 14th there was a whopping 34 inches of snow on the ground in Portland. Even with all that snow, there was only 2 inch left when April began. March 1993 was also a very cold month averaging nearly 4 degrees below average. I expect this March to average about as cold.

Assuming 6 to 12 more inches of snow falls between now and April 1, the ground should be bare between March 25 and April 3. There will still be piles of snow in places, but of the snow that’s here now, nearly all of it will disappear in March. Many spring sports will need to be practicing inside for a while, but unless we have an extreme amount of snow next month, the grass will be exposed about the same time as usual.