Combination of snow and rain.
Depth represents precipitation per unit area.
Cannot use data from one area to another. The record at a station has to be checked for consistency if the gage has been relocated, a new gage has been installed, etc. Double mass analysis It is used to detect if data at a site have been subjected to significant change in magnitude due to external factors. This is a more common adjustment. All these four parameters are needed to adequately describe an event and specify its magnitude.