Heavy snow in large swaths of Japan has killed 17 and injured more than 90 people and left hundreds of homes without power, disaster management officials said Monday. Powerful winter fronts have dumped heavy snow in northern regions since last week, stranding hundreds of vehicles on highways, delaying delivery services and causing 11 deaths by Saturday. More snowfall over the Christmas weekend brought the number of dead to 17 and injured to 93 by Monday morning, according to the Fire and Disaster Management Agency. Many of them had fallen while removing snow from the roofs or were buried underneath thick piles of snow sliding off rooftops, The Associated Press reported. Municipal offices in the snow-hit regions urged residents to use caution during snow removal activity and not to work alone. The disaster management agency said a woman in her 70s was found dead buried underneath a thick pile of rooftop snow that suddenly fell on her in Yamagata prefecture's Nagai City, about 300 kilometers (180 miles) north of Tokyo, where snow piled up higher than 80 centimeters (2.6 feet) Saturday. In Niigata, known for rice growing, some makers of mochi, or sticky rice cakes that are staple for New Year's celebration meals, said there have been delivery delays and their mochi may not reach their customers in time. Many parts of northeastern Japan reported three times their average snowfall for the season. Heavy snow knocked down an electric power transmission tower in Japan’s northernmost main island, leaving about 20,000 homes without power on Christmas morning, though electricity was restored in most areas later that day, according to the economy and industry ministry. Dozens of trains and flights were also suspended in northern Japan through Sunday, but services have since mostly resumed, according to the transportation ministry.