Is it ever too cold to snow?

No, it can snow even at incredibly cold 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 with relatively warm air temperatures near the ground - typically 15° F or warmer since air can hold more water vapor at warmer temperatures.

Why can snow fall when temperatures are above freezing?

Snow forms in the atmosphere, not at the surface. So snow can fall when surface temperatures are above freezing as long as atmospheric temperatures are below freezing and the air contains a minimum moisture level (the exact level varies according to temperature).

Is it true that there is one inch of water in every ten inches of snow that falls?

The water content of snow is more variable than most people realize. While many snows that fall at temperatures close to 32° F and snows accompanied by strong winds do contain approximately one inch of water per ten inches of snowfall, the ratio is not generally accurate. Ten inches of fresh snow can contain as little as 0.10 inches of water up to 4 inches depending on crystal structure, wind speed, temperature, and other factors. The majority of U.S. snows fall with a water-to-snow ratio of between 0.04 and 0.10.

Is snow edible?

Clean snow is certainly edible. Snow in urban areas may contain pollutants that one should not eat but they would probably be in such low concentrations that it might not matter. Still, eating snow should be restricted to "wilderness" areas. Sometimes snow contains algae which gives it a red color. This snow can be eaten and some say it actually tastes "good" but we have never tried it.

Why does snow crunch when you step on it? At what temperature does it crunch?

Snow is made of ice crystals. Ice crystals have six points. One snowflake can consist of multiple crystals. There are gaps between the points of a crystal that are empty, except for air. When snow falls to the ground, air is trapped inside of that layer of snow. You have probably noticed that when snow is stepped on, it gets compressed. The air gets pushed out of the snow. The sound you hear could be the sound of the ice crystals as they break. Try it with ice cubes. They make a crunching sound when they are broken. Also, on a sunny day, the surface layer of snow can melt, due to thermal heating. When the sun goes down and temperatures drop, that top layer refreezes into a thin crust of ice. If you step on it, you are breaking that top crust, resulting in a "crunching" sound. The crunching sound is less related to temperature and more related to the structure of the snow. The older the snow, the more compacted and icy it becomes.

Why is snow deep in spots and not others?

At the local scale, say from your backyard to the size of your neighborhood or town, this would be mainly due to wind during and after the storm and melting due to sun after the storm. At the larger scale, say the state of MN, it would also depend on the storm track - were you in the middle of the storm

Why is snow a good insulator?

Fresh, undisturbed snow is composed of a high percentage of air trapped among the lattice structure of the accumulated snow crystals. Since the air can barely move, heat transfer is greatly reduced. Fresh, uncompacted snow typically is 90-95 percent trapped air.

Can there be thunder and lightning with a snow storm?

Thunder and lightning can be associated with snowstorms but they are rare and occur more often near the coast.

How big can snowflakes get?

Snowflakes are agglomerates of many snow crystals. Most snowflakes are less than one-half inch across. Under certain conditions, usually requiring near-freezing temperatures, light winds, and unstable, convective atmospheric conditions, much larger and irregular flakes close to two inches across in the longest dimension can form. No routine measure of snowflake dimensions are taken, so the exact answer is not known.

What is lake effect snow?

Lake effect snow is "snow showers that are created when cold dry air passes over a large warmer lake, such as one of the Great Lakes, and picks up moisture and heat."