Q: What affects the way snow forms and falls?

A: With arctic conditions expected throughout the week, many may be wondering what affects snowfall besides temperature.

For instance, sleet starts off as snow in the upper atmosphere. As it falls, it melts and then refreezes into the chunks of ice that we see at the surface, meteorologist Jeff Warner said.

Whether or not a snowstorm is considered a blizzard or not actually has nothing to do with how much snow accumulates, he said. The technical definition of a blizzard is that if there is visibility of a quarter mile or less for three hours or more and winds with frequent gusts of more than 35 mph, it is considered a blizzard, he said.

The snow does not have to be falling, as a blizzard can form when snow already on the ground gets blown around, Warner said. Snow forms in the atmosphere around tiny particles called precipitation nuclei, he said.

Todd Miner, instructor of meteorology at Penn State, said these nuclei help determine the shape of the ice crystals that make up a snowflake.

"When you look out the window on a cold day you see feathery frost patterns on the window. The way in which a snowflake forms is similar," he said. "If there is dust and dirt, water vapor will condense or freeze, and the ice nuclei can dictate the shape of the ice crystal."

The size of a snowflake is dependent on humidity and temperature, Miner said.

"[Size] is related to what the humidity is where they're falling and the temperature of air where they're forming. Depending on the combination you end up getting different sizes," he said.

-- Compiled by David Collins