Citizen science data are necessary because many existing weather monitoring technologies have little or no coverage in mountain regions. Remote sensing platforms have poor spatiotemporal coverage, and the reanalysis products that rely on remote sensing data have spatially variable performance. Our ability to infer precipitation phase from models is limited. These model-based methods struggle at air temperatures near freezing and often have trouble identifying freezing rain from warm snow. Even complex machine learning techniques offer only marginal improvements over traditional phase partitioning methods. 

All of these challenges point to the valuable role that observations made by people have in tackling these large challenges in meteorology and hydrology. 

A primary goal of collecting rain, snow, and mixed precipitation observations is to improve satellite-derived estimates of precipitation phase from the Global Precipitation Monitoring (GPM) mission. We have compared Mountain Rain or Snow data to numerous meteorologic and geospatial rain-snow partitioning methods, helping to identify where these methods struggle and pointing to potential routes to improvement. 

Our team is also examining ways that crowdsourced data can improve the forecasting of winter weather and hazards, such as rain-on-snow events and avalanches, using the National Blend of Models. We have also explored preliminary work  that compares  distrometer and micro rain radar estimations of snow levels with our crowdsourced observations. 

Finally, our work has contributed to effective practices for citizen science project design. We have innovated methods for training, activating, and communicating with observers through text-based communication. We also developed a science communication method for reporting results back to community observers (known as a “report back”). These methods are designed to be scalable, easily customized for other projects. 

Mountain Rain or Snow will advance our knowledge of the water cycle in mountain regions, knowledge of weather and winter weather hazards, and improve NASA’s Earth observational capabilities for winter storms, including rain-on-snow events. 

Mountain Rain or Snow is supported by NASA.

The full title of this project is “Using Citizen Science Observations to Monitor the Rain-Snow Transition of the Western US and Improve Satellite Estimates of Precipitation Phase”. It is funded by a grant from the National Aeronautics and Space Administration (NASA) ROSES Earth Science Research Program. Any opinions, findings, conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of NASA. For more information about NASA citizen science, visit science.nasa.gov/citizenscience  or nasa.gov/get-involved.