Logistical constraints have caused data collection in seasonally snow covered areas to generally be on a campaign basis with limited instrumentation. The problems of winter access, cold air temperatures, and blowing snow cause both equipment malfunctions and problems with consistent and timely maintenance. At the Long-Term Ecological Research program network site in an alpine area of Colorado we have been operating a meteorological station and subnivean (below snow) laboratory at 3517 m since the spring of 1994 to collect information that will allow us to better understand snow-surface energy exchanges and the mass flux of water during snowmelt. This unique and high-quality data set was designed to measure the meteorologic and hydrologic parameters necessary to compute the surface energy and snowpack mass balances at a point. All meteorological parameters are directly measured. Turbulent fluxes are calculated using the aerodynamic profile method. The timing and magnitude of snowmelt is measured with 18 snow lysimeters. Meteorologic parameters and energy fluxes are available at 10-min, hourly, and daily time steps. Complementary information includes a high-resolution digital elevation model, snowpack parameters, and stream discharge. ¿ 1999 American Geophysical Union