Disturbances in a moist westerly flow began in the afternoon of 12/12/2019 and lasted through late evening of 12/14/2019. This storm was unusually powerful and many snowpacks have seen an increase of 30-50% throughout the north. Winter storm warnings and watches in effect. Significant snowfall and SWE. Avalanche danger rising to High. Lots of natural and human triggered avalanches.