Recent winter storms and climate changeĮxtra-tropical storms in winter form and develop on differences in temperature, which are greatest between continents and adjacent oceans. It could be much more because the warm moist buoyant air may also contribute to intensification of the storm itself. How does this play out when temperatures are below freezing? Temperatures in the Goldilocks range of between about 28☏ and 32☏, accompanied by moisture, mean more snow: indeed, the amount of snowfall at 32☏ would be at least double that at 14☏. Accordingly, if there is more moisture in the environment, it rains (or snows) harder. This moisture, as water vapor, is gathered by the storm winds, brought into the storm, concentrated and precipitated out. In all storms, the main source of precipitation is the moisture already in the atmosphere at the start of the storm. The lifting of air comes mostly from storms, especially in warm fronts, as warm air moves over cooler air, or cold fronts, as cold air pushes under warmer air. At some point, it can no longer hold as much moisture and so the moisture condenses into a cloud and ultimately forms rain or snow. When a parcel of air containing water vapor is lifted, it moves into lower pressure, expands and cools. In fact, this relationship is fundamental to why it rains (or snows). That translates into a big difference in moisture across temperature differences: At 50☏ (10☌) the water-holding capacity of air is double that at 32☏ (0☌) and at 14☏ (-10☌) the value is only 24% that at 50☏. Some complications come in as the ice phase enters, but we set those aside for now. The physics behind this phenomenon is governed by a basic law that tells us the maximum amount of moisture in the atmosphere increases exponentially with temperature – that is, the warmer the atmosphere, the more moisture the air can hold and thus, the more potential for precipitation.įor most conditions at sea level, there’s a rule of thumb that says the atmosphere can hold 4% more moisture per one degree Fahrenheit increase in temperature. The first blizzard of 2015 as viewed from space. And these conditions are becoming more likely in mid-winter because of human-induced climate change. So there is a “Goldilocks” set of conditions that are just right to result in a super snow storm.
Of course, once it gets much above freezing point, the snow turns to rain. Under cold conditions, the snow is likely to consist of very small crystals and sometimes is very light and fluffy and like “diamond dust”.īy contrast, the heaviest snowfalls occur with surface temperatures from about 28☏ to 32☏ – just below the freezing point.
That’s because the amount of moisture the atmosphere can hold depends very strongly on temperature. There is a saying that it can be “ too cold to snow”! Of course, this is a myth but it has a basis in fact because the atmosphere gets freeze dried when it is very cold. Studying these factors reveals that there is a higher chance of heavy snow storms in North America but the length of the snow season is already shrinking due to global warming. Then, we can look at how climate change is affecting those conditions, especially temperatures in the atmosphere and oceans, during winters. To understand the connection, we need to look at what conditions make for the heaviest snowfalls. Consequently, deniers of climate change have used recent snow dumps to cast doubt on a warming climate from human influences. As first glance, asking whether global warming results in more snow may seem like a silly question because obviously, if it gets warm enough, there is no snow.
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