Why don't snowstorms produce thunders and lighting?

               

Becouse during the summer, the lower atmosphere is full of warm, humid air. Above that, it's cold and full of ice crystals. As the warm air rises, it carries water vapour with it, these molecules brush against the ice crystals, and this friction creates an electric field in the cloud -- like scuffing your feet across a carpet. The ice crystals gain a slight positive charge, and the updraft carries them to the top of the cloud, giving the cloud's bottom a net negative charge. Once the difference between the negatively charged cloud bottom and the positively charged ground becomes great enough, a bolt arcs between them.

But in snowy months, the atmosphere is cold and dry throughout, so there's no updraft to create friction within the clouds. Wind stirs the molecules and crystals some, but that action rarely generates a strong enough electric field to spark lightning.

The circunstances that need snow storms are:

-Is essential that the air is very cold.It has to be below

freezing for snow to fall.Also there has to be enough moisture in the air.the temperature must be cold both up in the clouds where snowflakes form, and down at ground level. If the air near ground level is too warm, the snow will melt on its way down, changing to rain or freezing rain.

       

    Eva Olarte Antón 1ºB ESO