Why when it snows, does the whole cloud not just freeze over?
435763
In order for snow to form the air must be supercooled. The process of snow formation starts w/ the Bergeron Process. This is also known as cold cloud precipitation.\n\nTiny ice particles form around condensation nuclei aka aerosols (pollen, dust, ash, salts, etc.) in the upper atmosphere.\n\nThey grow larger & larger until they can no longer be supported & gravity takes over.\n\nThe reason why the whole cloud won't freeze is b/c they are individual ice crystals. There is no way that they could stay suspended long enough to grow large enough to stick together.\n\nSo your answer is gravity takes over!
67967
Ice is not transparent; it's actually translucent. This means that the light photons don't pass right through the material in a direct path -- the material's particles change the light's direction. This happens because the distances between some atoms in the ice's molecular structure are close to the height of light wavelengths, which means the light photons will interact with the structures. The result is that the light photon's path is altered and it exits the ice in a different direction than it entered the ice. \n\nSnow is a whole bunch of individual ice crystals arranged together. When a light photon enters a layer of snow, it goes through an ice crystal on the top, which changes its direction slightly and sends it on to a new ice crystal, which does the same thing. Basically, all the crystals bounce the light all around so that it comes right back out of the snow pile. It does the same thing to all the different light frequencies, so all colors of light are bounced back out. The "color" of all the frequencies in the visible spectrum combined in equal measure is white, so this is the color we see in snow, while it is not the color we see in the individual ice crystals that form snow.
726978
The warm air pushes the moisture higher into the colder air layers....as the moisture droplets freeze together  they fall and enter the warm air currents which pushes them back up to the cold layers..this happens until enough layers are built up, that the updrafts can't support the weight and the ice falls to the ground in the form of hailstones.
500
A cloud compsition is primarlly just billions of drops of water or ice.  When such a cloud formation has an influx of water/ice, ie it's mass increases to include more water/ice, light finds it hard to pass through the mass, thus making it darker for us to see.\n\nIn a normal cloud, light can pass through the water/ice within the cloud and we see it as a distorted white/bluish/greyish/greenish hue.  But when the cloud is too thick with water/ice, the light doesn't pass through so easily and we see a darker spectrum.
170380
Not a common occurrence, but it certainly does happen...as it did this morning here.  Typically precipitating clouds in the winter are much less developed than summer thunderstorms, but occasionally more developed storm clouds do occur in winter and generate lightning (and thunder) just as they do in summer.  Expect a short and intense snowfall when it happens.
833095
an updraft of cold air freezes water droplets into crystle. All of them are 6 sided, and EVERY ONE of them is different - amazing eh.\n\nyou can go to http://snowflakebentley.com/snowflakes.htm for cool pics and \nhttp://www.kidzworld.com/site/p1587.htm\nto see how snow is formed.
725440
what you see on the cirrus clouds (the streaks, or tails) and slowly fading away is actually snow. blown byt the winds =)
17071
It's called "thunder snow" & it's rare, since cold weather usually doesn't have the right conditions for cumulonimbus clouds to form. However if the conditions are right (warmer air & moisture) thunderstorms can form in the winter as well.\n\nIt's pretty wild, I've seen it a couple times in the northeast. It's especially amazing at night, the lightning creates a giant strobe effect.
18597
To save you some time, here is a great description in plain English:\n\nIt all begins when bitter cold air dives across the Great Lakes. As the cold air flows over the warm water, the relatively warm lake water heats the air's bottom layer as lake moisture evaporates into the cold air.\n\nSince warm air is lighter - less dense - than cold air, the heated air rises and begins to cool.\n\nAs the air cools, the moisture that evaporated into it condenses and forms clouds, and snow begins falling from the cloud if the air is humid enough.\n\nThe wind pushes the clouds over the land. As this happens, friction with the ground, which is greater than the friction between the lake's water and the moving air, slows the winds. This causes the air that's carrying the clouds to "pile up" - meteorologists call this "convergence."\n\nConvergence increases the amount of snow that's falling on the land compared with the amount falling on the lake.\n\nAs the wind continues inland it runs into hills, sometimes only a few miles from the lake, which forces the air to rise, which cools it. As the air cools, more humidity condenses to create even more snow. This is why the heaviest lake effect snow falls on hills inland from the great lakes. \n\nThe source also has an outstanding graphic depiction and explanation.
825004
Probably just the weather changing quickly ? We had a thunderstorm a few weeks ago, except it was snowing with it. Really warm before it and really cold afterwards... I'm sure it's nothing to alarm yourself over.
364366
As air rises to get over the mountain, it cools.  Cooler air can't carry as much water vapor as warmer air, so cloud droplets form.
906375
All I know about freezing rain is that it hardens (freezes) once it hits the ground.
707708
The droplets that make up clouds freeze all the time, but clouds don't freeze into solid blocks because the particles are too dispersed. In fact, most of the high-altitude clouds you see are made up of frozen droplets.
1020465
I would say winter, you said summer might be, but those clouds usually are from thunderstoms, which die out rather quickly, but winter makes snow storms that can last for days, so, if I was to give an answer, I would say winter. Also, I live in Arizona, so you don't have to trust me on this one :>)
353678
The water droplets are very tiny and present a lot of surface area (compared to their volume) to the air. Rapid evaporation from the surface of the droplets cools them sufficiently to freeze.
5861
No.  The cloud will form when the ambient temperature inside the cloud is lower than the dew point.  The moisture may actually form snow (on a summer day!) which melts on the way down to form rain.  The temperature outside the cloud may be less relevant because clouds often form when a column of moisture-laden air rises locally condensing into a  cloud right above the column.
392443
That is an interesting question.  What is snow made of?\nWater, right? Except it is water frozen in a special\nway, by accretion of little bits as the snowflake\ndrops through the atmosphere, so that snow is pretty\nrandom stuff, compared to ice which is also frozen\nwater, but which has all the water molecules nicely\nlined up which makes it transparent.  The randomness\nof snow means that when light strikes the snow it\ngets scattered in all directions, and all colors are\njumbled up, so when you look at snow all you see is\nthe jumble, which shows up as white light.  When\nit melts, it just turns into water (and usually\ndisappears into the ground) which does not have the\nkind of randomness snow has at the level of the\nwavelengths of visible light.  (Visible light\nhas wavelengths much longer than the size of molecules).\nSo, the "white" did not really exist on its own -\nit was a property of the arrangement of the water molecules\nin snow, and disappears as soon as that arrangement is\nchanged.\n\nDoes this help?