Is It Ever Really Too Cold To Snow?
Having withstood a few snowy Midwestern winters in our time, we’re not sure we would want to test this hypothesis personally. Luckily, meteorologists have.
No, it never gets too cold to snow, but at extremely low temperatures the amount of snow accumulation on the ground is likely to be much lower than at 25 degrees Fahrenheit. According to Raymond E. Falconer, of the Atmospheric Sciences Research Center, SUNY at Albany, there is so little water vapor available at subzero temperatures that snow takes the shape of tiny ice crystals, which have little volume and do not form deep piles. But at warmer temperatures more water vapor is available, “so the crystals grow larger and form snowflakes, which are an agglomerate of ice crystals.” The warmer the temperature is, the larger the snowflakes become.
What determines the size of the initial snow crystals? It depends upon the distribution of temperature and moisture from the ground upon the distribution of temperature and moisture from the ground up to the cloud base. If snow forming at a high level drops into much drier air below, the result may be no accumulation whatsoever. In the condition known as “virga,” streaks of ice particles fall from the base of a cloud but evaporate completely before hitting the ground.
Having withstood a few snowy Midwestern winters in our time,…