'A stupid mistake': Skiers, snowboarders trigger multiple avalanches in Tahoe FacebookTwitterEmail 2of5 3of5 4of5 Backcountry skiers and snowboarders triggered multiple avalanches in the Tahoe region over the holiday weekend.Courtesy of Sierra Avalanche CenterShow MoreShow Less 5of5 Last Friday started as one of those perfect winter days in Tahoe. A storm dropped about a foot of new snow during the night, and in the morning, the sky cleared. By the end of the day, however, the Sierra Avalanche Center had received numerous reports of avalanches. Some slides occurred naturally; however, many were triggered by backcountry skiers and snowboarders. That day, the snowpack had several big issues lurking that were created by the overnight storm. First thing in the morning, the Sierra Avalanche Center posted its forecast, a daily briefing that gives backcountry skiers and snowboarders (as well as people who drive snowmobiles) lifesaving knowledge about what’s happening in the snowpack and the weather. The center noted that storm slabs — dense blocks of snow that build up during a blizzard and are prone to fracturing and sliding — were one of its big concerns. On Friday, the center rated the avalanche danger as “considerable,” which meant that conditions were unstable and skiers and snowboarders were likely to trigger avalanches.