snow_form
snow_form

Whether winter storms produce snow relies heavily on temperature, but not necessarily the temperature we feel here on the ground. Snow forms when the atmospheric temperature is at or below freezing (0 degrees Celsius or 32 degrees Fahrenheit) and there is a minimum amount of moisture in the air. If the ground temperature is at or below freezing, the snow will reach the ground. However, the snow can still reach the ground when the ground temperature is above freezing if the conditions are just right. In this case, snowflakes will begin to melt as they reach this higher temperature layer; the melting creates evaporative cooling which cools the air immediately around the snowflake. This cooling retards melting. As a general rule, though, snow will not form if the ground temperature is at least 5 degrees Celsius (41 degrees Fahrenheit).

snow_form

While it can be too warm to snow, it cannot be too cold to snow. Snow can occur even at incredibly low temperatures as long as there is some source of moisture and some way to lift or cool the air. It is true, however, that most heavy snowfalls occur when there is relatively warm air near the ground—typically -9 degrees Celsius (15 degrees Fahrenheit) or warmer—since warmer air can hold more water vapor.

snow_form
snow_form

Because snow formation requires moisture, very cold but very dry areas may rarely receive snow. Antarctica’s Dry Valleys, for instance, form the largest ice-free portion of the continent. The Dry Valleys are quite cold but have very low humidity, and strong winds help wick any remaining moisture from the air. As a result, this extremely cold region receives little snow.Snow on the ground
The character of the snow surface after a snowfall depends on the original form of the crystals and on the weather conditions present when the snow fell. For example, when a snowfall is accompanied by strong winds, the snow crystals are broken into smaller fragments that can become more densely packed. After a snowfall, snow may melt or evaporate, or it may persist for long periods. If snow persists on the ground, the texture, size, and shape of individual grains will change even while the snow temperature remains below freezing, or they may melt and refreeze over time, and will eventually become compressed by subsequent snowfalls.

Over the winter season, the snowpack typically accumulates and develops a complex layered structure made up of a variety of snow grains, reflecting the weather and climate conditions prevailing at the time of deposition as well as changes within the snow cover over time.

snow_form
climate teaching

How big can snowflakes get?
Snowflakes are accumulations of many snow crystals. Most snowflakes are less than 1.3 centimeters (0.5 inches) across. Under certain conditions, usually requiring near-freezing temperatures, light winds, and unstable atmospheric conditions, much larger and irregular flakes can form, nearing 5 centimeters (2 inches) across. No routine measure of snowflake dimensions are taken, so the exact size is not known.

 

reference-nsidc site

 

************************

#recentclimate

weather,weather tomorrow,weather today,weather forecast, weather report,forecast,weather today at my location,weather update,google weather,weather hourly,temperature today,weather this week,today weather report,hail,weather map,thunderstorm,weather forecast today
yahoo weather,live weather,insat image,weather in my location,today’s forecast,windy weather,snow squall,saturday weather,temperature now,weather app,rain today,the weather today,weather forecast tomorrow,weather news,imd satellite,weather satellite,meteorologist
my weather,wind forecast,hourly forecast,weather today at my location hourly,wind map,best weather app,thursday weather,weather station,weather warnings,openweathermap,snow storm,accuweather app,google weather app,live weather map,world weather
weather today hourly,live weather report,weather tomorrow morning,weather location,wind chill,weekly forecast,weather tomorrow hourly
weather information,accuweather forecast,snowfall weather forecast,strand weather,weather us,weather satellite image,world weather map
weather and climate,weather tomorrow rain,weather forecast near me,weather forecast rain,nurburgring weather,weather widget,climate
greta thunberg,global warming,climate change,causes of global warming,causes of climate change,

By JC

Consultation on Climate Change & Risk Management