1 http://www.weatherquestions.com/What_causes_snow.htm http://www.discoverymagazine.com/digger/d93dd/d9304dd.html http://meteorologyclimatology.suite101.com/article.cfm/what_causes_sno w_sleet_and_freezing_rain http://www.fema.gov/kids/thwhat.htm http://environment.nationalgeographic.com/environment/natural-disaster s/lightning-profile.html?source=sem_G2305c_ESV&esvcid=S1272425113_ADOG OC_AGI3831008_ADI5424867_TRMbGlnaHRuaW5nJTIwdHJhY2tlcg%3d%3d_RFDd3d3Ln dpc2VnZWVrLmNvbQ%3d%3d&utm_source=google&utm_medium=CPC&utm_term=light ning%20tracker&utm_content=S1272425113_ADOGOC_AGI3831008_ADI5424867_TR MbGlnaHRuaW5nJTIwdHJhY2tlcg%3d%3d_RFDd3d3Lndpc2VnZWVrLmNvbQ%3d%3d&utm_ campaign=Environment-+Content&gclid=CP7Ijve4qKECFYd-5QodpQz4FA http://en.wikipedia.org/wiki/Lightning