Dec 25 (Reuters) - A deadly blizzard paralyzed Buffalo, New York, on Christmas Day, trapping motorists in their cars, knocking out electricity to thousands of homes and raising the death toll from a severe winter storm system that has chilled much of the United States for days.At least 30 people have died in U.S. weather-related incidents, according to an NBC News tally, since a deep freeze gripped most of the nation, coupled with snow, ice and howling winds from a storm that roared out of the Great Lakes region late last week.The latest victims included some found in cars and some in snow banks, Poloncarz said, adding that the death tally might rise further.Despite a ban imposed on driving since Friday, hundreds of Erie County motorists were stranded in their vehicles over the weekend, with National Guard troops called in to help with rescues complicated by white-out conditions and drifting snow, Poloncarz said.In Kentucky, officials confirmed three storm-related deaths since Friday, while at least four people were dead and several injured in auto-related accidents in Ohio, where a 50-vehicle pileup shut down the Ohio Turnpike in both directions during a blizzard on Friday."