A method of modeling the frequency characteristics of daily snow amount, for stochastic simulation of rain-on-snowmelt events

In the mountainous West, rain-on-snowmelt (R/SM) storms are common events having extreme effects: warm winter rains combine with snowmelt to generate water inputs greater than either could produce alone, which can then result in flooding and lansdslides.A stochastic approach to estimation of R/SM properties uses a computer model to create a series of simulated storms, with the realizations examined for insight into the storms' effects. My study involves modeling of storms, and the resultant snowmelt and percolation, based on data from the Cascade Range of Washinton. I have adpated a mixed-probability distribution, with regression against date and elevation, to estimate the probable amount of snow on the ground when the storm occurs.These methods can be used to generate frequency curves, define the location of the transient snow zone, and compare the effects of R/SM events on cleared and forested land.