ESTIMATING GROUND SNOW LOADS USING LOCAL CLIMATOLOGICAL DATA

Ground snow loads have traditionally been estimated from data, in the form of accumulated water-equivalent snow depth (density), collected b y the National Weather Service (NWS) and the Soil Conservation Service (SCS), at so-called first-order weather stations. Extensive data rela ted to snow depth, with the exception of water equivalents, are availa ble from other weather stations (other NWS stations, cooperative state and local agencies' stations, etc.). In this paper, we present a meth od, using first-order station data, to relate water-equivalent depth t o snow depth and daily temperature. A locality with a similar weather pattern as the first-order station that maintains an appropriate weath er database (i.e., snow depth and daily temperature) was identified. U sing the developed relationship between water equivalents, snow depth, and daily temperature, we convert snow depth to density (i.e., water equivalents) for the local data source. This procedure allows us to si gnificantly expand our ground snow load database, better determine the proper statistical distribution for annual maximum events, and more a ccurately estimate design ground snow loads. We illustrate the method using climatological data from a NWS first-order station (including wa ter equivalents), and a nearby cooperative state weather station.