A method of forecasting snowfall accumulation, the method comprising: identifying a predicted location and a predicted time period of a snowstorm; receiving a plurality of weather forecasts for the predicted time period in the predicted location; for each of the plurality of weather forecasts, determining a snowfall accumulation forecast; forming an ensemble histogram by identifying a series of consecutive, non-overlapping snowfall accumulation ranges and determining how many of the snowfall accumulation forecasts are in each of the snowfall accumulation ranges; calculating a probability density function representing the relative likelihood of snowfall accumulation amounts based on the ensemble histogram; forming a snowfall probability distribution based on the probability density function, the snowfall probability distribution including: the most likely snowfall accumulation range and the probability that snowfall accumulation in the predicted location over the predicted time period will be within the most likely snowfall accumulation range; at least one higher snowfall accumulation range and the probability that snowfall accumulation in the predicted location over the predicted time period will be within the higher snowfall accumulation range; and at least one lower snowfall accumulation range and the probability that snowfall accumulation in the predicted location over the predicted time period will be within the lower snowfall accumulation range; generating a snowfall probability forecast that includes the most likely snowfall accumulation range and the probability that snowfall accumulation in the predicted location over the predicted time period will be within the most likely snowfall accumulation range; and outputting the snowfall probability forecast. identifying a predicted location and a predicted time period of a snowstorm; receiving a plurality of weather forecasts for the predicted time period in the predicted location; for each of the plurality of weather forecasts, determining a snowfall accumulation forecast; forming an ensemble histogram by identifying a series of consecutive, non-overlapping snowfall accumulation ranges and determining how many of the snowfall accumulation forecasts are in each of the snowfall accumulation ranges; calculating a probability density function representing the relative likelihood of snowfall accumulation amounts based on the ensemble histogram; forming a snowfall probability distribution based on the probability density function, the snowfall probability distribution including: the most likely snowfall accumulation range and the probability that snowfall accumulation in the predicted location over the predicted time period will be within the most likely snowfall accumulation range; at least one higher snowfall accumulation range and the probability that snowfall accumulation in the predicted location over the predicted time period will be within the higher snowfall accumulation range; and at least one lower snowfall accumulation range and the probability that snowfall accumulation in the predicted location over the predicted time period will be within the lower snowfall accumulation range; the most likely snowfall accumulation range and the probability that snowfall accumulation in the predicted location over the predicted time period will be within the most likely snowfall accumulation range; at least one higher snowfall accumulation range and the probability that snowfall accumulation in the predicted location over the predicted time period will be within the higher snowfall accumulation range; and at least one lower snowfall accumulation range and the probability that snowfall accumulation in the predicted location over the predicted time period will be within the lower snowfall accumulation range; generating a snowfall probability forecast that includes the most likely snowfall accumulation range and the probability that snowfall accumulation in the predicted location over the predicted time period will be within the most likely snowfall accumulation range; and outputting the snowfall probability forecast.