Quote:
Originally Posted by Merrymeeting
"...but without the really bitterly cold weather of mid-winter..." --- Certainly don't understand this part of your theory. This was one of the most bitterly cold winters on record. It's why most of the snow storms had such light, fluffy snow. But like insulation, the trapped air spaces helped keep the ground insulated and allowed the earths heat from below to keep the frost line from going too deep.
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Deep ground is a source of heat; the temperature down there reflects the average year round temperature of the air above it over centuries. In winter, that heat is moving upward toward the cold, establishing a temperature profile that starts at deep ground temperature way down, dropping to 32 F up at the depth of frost, and dropping still further on up to near the surface. The temperature of the topmost layer will swing up and down somewhat according to air temperature. The lower the average day/night air temperature, the deeper the frost line gets.
March, while certainly much colder this year than the typical March, still was not as cold, on average, as January and February of this year. Thus March ought to have seen the frost line recede upward somewhat as the month progressed, while the cooler than average air temperature would have delayed thawing from the surface downward. While this might be a reasonable explanation of what I observed locally, I do have to wonder whether the effect was really important enough or if what I saw simply reflected the lower total water content of this year's snowfall.
Certainly the dry, fluffy nature of the snow this year would both reduce the total water content and also insulate the ground under it, keeping the frost level up higher, except perhaps under plowed roadways. I imagine that some road sections, due to their location and makeup of the material constituting the top foot or more, always will be trouble spots, no matter how deep the frost got.