Mountain glaciers are closely coupled to climate processes, ecosystems, and regional water resources. To enhance physical understanding of these connections, the USGS maintains a collection of glacier mass balance and climate data across the western United States and Alaska. In some cases, records of glacier mass balance extend back to the mid-1940s. These data have been incorporated from various sources, primarily original USGS studies, but also including work from the University of Alaska, and the Juneau Icefield Research Program (JIRP). The core of this collection is composed of mass balance data from the USGS Benchmark Glaciers. These five glaciers are Lemon Creek Glacier, AK (1953 -Present), South Cascade Glacier, WA (1958 - Present), Gulkana and Wolverine glaciers, AK (1966 - Present), and Sperry Glacier, MT (2005 - Present). Datasets from each benchmark glacier are composed of, at a minimum, point mass balances, glacier hypsometry, daily temperature and precipitation, geodetic mass balances, and glacier-wide mass balances. Data from other glaciers within this collection may be less complete, continuous, or representative as data from the benchmark glaciers. In these cases, we urge users to carefully inspect the associated metadata of each specific data release for further details.

Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek Glacier, AK to compliment data collected by the Juneau Icefield Research Program (JIRP; Pelto and others, 2013). Direct field measurements of point glaciological data are combined with weather and geodetic data to estimate the seasonal and annual mass balance at each glacier in both a conventional and reference surface format (Cogley and others, 2011). The analysis framework (O'Neel, 2019; prior to v 3.0 van Beusekom and others, 2010) is identical at each glacier to enable cross-comparison between output time series. Vocabulary used follows Cogley and others (2011) Glossary of Glacier Mass Balance.

Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek Glacier, AK to compliment data collected by the Juneau Icefield Research Program (JIRP; Pelto and others, 2013). Direct field measurements of point glaciological data are combined with weather and geodetic data to estimate the seasonal and annual mass balance at each glacier in both a conventional and reference surface format (Cogley and others, 2011). The analysis framework (O'Neel, 2019; prior to v 3.0 van Beusekom and others, 2010) is identical at each glacier to enable cross-comparison between output time series. Vocabulary used follows Cogley and others (2011) Glossary of Glacier Mass Balance.

This dataset contains point raw glaciological field data. Snow pit and snow core data give detailed information on snow density through the measured snow column. Snow depth measurements are collected via snow probe and in some snow pits or snow cores that extend the full depth of the snowpack to the glacier's surface. Ablation stakes allow point measurement of both snow depth and snow melt against the reference of the labeled stake. Draw wires provide additional measurements of snow and ice melt, against the invariant reference of the labeled wire. It is used to calculate point mass balance, or the mass balance at a specified location on the glacier.

Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek and Taku glaciers, AK to compliment data collected by the Juneau Icefield Research Program (JIRP; Pelto et al., 2013). Direct field measurements of point glaciological data are combined with weather and geodetic data to derive glacier-wide seasonal and annual surface mass balance solutions of each glacier in conventional and reference surface formats (Cogley et al., 2011). Additional details on the calculation of glacier-wide surface mass balance are described in Van Beusekom et al. (2010). This dataset contains point raw glaciological field data. Snow pit and snow core data give detailed information on snow density through the measured snow column. Snow depth measurements are collected via snow probe and in some snow pits or snow cores that extend the full depth of the snowpack to the glacier's surface. Ablation stakes allow point measurement of both snow depth and snow melt against the reference of the labeled stake. Draw wires provide additional measurements of snow and ice melt, against the invariant reference of the labeled wire. It is used to calculate point mass balance, or the mass balance at a specified location on the glacier.

Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek Glacier, AK to compliment data collected by the Juneau Icefield Research Program (JIRP; Pelto and others, 2013). Direct field measurements are combined with weather data and imagery analyses to estimate the seasonal and annual mass balance at each glacier in both a conventional and reference surface format (Cogley and others, 2011). High-altitude measurements of meteorological data have been collected since the beginning of the USGS Benchmark Glacier Program adjacent to glaciers in order to support related science. This portion of the data collection includes select weather data that has received basic quality control and assurance. Data is released at three different levels of processing, level 0, 1 and 2. Level 0 data contains compiled raw data, before QC procedures are applied, at the original timestep recorded by the instrument. Level 1 data has received a plausible value check, and minimal manual error identification (e.g. errors noted on field visits). Level 2 data has been through more extensive quality control procedures and is provided at both the original instrument timestep as well as aggregated hourly and daily values. However, beyond the procedures detailed in this document, no additional steps have been taken to manually assure quality of the data. Data outside the main record of temperature and precipitation at each site should be considered preliminary, and be utilized with increased scrutiny.

Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek Glacier, AK to compliment data collected by the Juneau Icefield Research Program (JIRP; Pelto and others, 2013). Direct field measurements are combined with weather data and imagery analyses to estimate the seasonal and annual mass balance at each glacier in both a conventional and reference surface format (Cogley and others, 2011). High-altitude measurements of meteorological data have been collected since the beginning of the USGS Benchmark Glacier Program adjacent to glaciers in order to support related science. This portion of the data release includes select weather data that has received basic quality control and assurance. Data is released at three different levels of processing, level 0, 1 and 2. Level 0 data contains compiled raw data, before QC procedures are applied, at the original timestep recorded by the instrument. Level 1 data has received a plausible value check, and minimal manual error identification (e.g. errors noted on field visits). Level 2 data has been through more extensive quality control procedures and is provided at both the original instrument timestep as well as aggregated hourly and daily values. However, beyond the procedures detailed in this document, no additional steps have been taken to manually assure quality of the data. Data outside the main record of temperature and precipitation at each site should be considered preliminary, and be utilized with increased scrutiny.

Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at key North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. The Juneau Icefield Research Program has measured glacier mass balance on Lemon Creek since the mid-1940s, with USGS providing complimentary seasonal measurements of Lemon Creek beginning in 2014 (JIRP; McNeil et al., 2020). Direct field measurements of point glaciological data are combined with weather and geodetic data to estimate the seasonal and annual mass balance at each glacier in both a conventional and reference surface format (Cogley and others, 2011). The analysis framework (O'Neel and others, 2019; Florentine and others, 2024; prior to v 3.0 van Beusekom and others, 2010) is identical at each glacier to enable cross-comparison between output time series. Vocabulary used follows Cogley and others (2011) Glossary of Glacier Mass Balance. This portion of the data release includes glacier wide mass balance, as well as the refined inputs used in these calculations. Input data are of three types: 1) time-variable area altitude distribution (AAD); 2) time series of point water balance at long term sites (with secondary sites given in recent years); 3) weather data from nearby stations, either installed along the glacier margins or taken from a nearby site if continuous glacier-adjacent data is unavailable. The USGS runs a coded analysis to transform the three input data types to the output glacier-wide data. Output data represent surface mass balance estimates. The output solution is a geodetically calibrated, conventional glacier-wide mass balance, which represents our preferred solution. Conventional glacier-wide mass balance from direct observations without calibration can be easily derived by using the geodetic calibration coefficients provided, if desired. We do not explicitly account for basal or englacial accumulation or ablation. Mass balances are reported in water equivalent (w.e.) units, and often represent integration of multiple field measurements. Whenever possible, we average multiple field measurements to account for surface roughness and measurement errors. These raw point measurements and other mass-balance related data are included in the larger USGS Benchmark Glacier Project Comprehensive Data Collection, available at https://doi.org/10.5066/P9AGXQSR Preliminary mass balance estimates for the current calendar year are provided, but do not include direct measurements of ablation after the date of the fall visit. Preliminary estimates of mass balance model this winter ablation for the current year. During subsequent field visits in the following calendar year, any ablation that occurred over the winter season is measured and used to revise the previously modeled estimate of mass balance.

Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at key North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. The Juneau Icefield Research Program has measured glacier mass balance on Lemon Creek since the mid-1940s, with USGS providing complimentary seasonal measurements of Lemon Creek beginning in 2014 (JIRP; McNeil et al., 2020). Direct field measurements of point glaciological data are combined with weather and geodetic data to estimate the seasonal and annual mass balance at each glacier in both a conventional and reference surface format (Cogley and others, 2011). The analysis framework (O'Neel and others, 2019; Florentine and others, 2024; prior to v 3.0 van Beusekom and others, 2010) is identical at each glacier to enable cross-comparison between output time series. Vocabulary used follows Cogley and others (2011) Glossary of Glacier Mass Balance. This portion of the data release includes glacier wide mass balance, as well as the refined inputs used in these calculations. Input data are of three types: 1) time-variable area altitude distribution (AAD); 2) time series of point water balance at long term sites (with secondary sites given in recent years); 3) weather data from nearby stations, either installed along the glacier margins or taken from a nearby site if continuous glacier-adjacent data is unavailable. The USGS runs a coded analysis to transform the three input data types to the output glacier-wide data. Output data represent surface mass balance estimates. The output solution is a geodetically calibrated, conventional glacier-wide mass balance, which represents our preferred solution. Conventional glacier-wide mass balance from direct observations without calibration can be easily derived by using the geodetic calibration coefficients provided, if desired. We do not explicitly account for basal or englacial accumulation or ablation. Mass balances are reported in water equivalent (w.e.) units, and often represent integration of multiple field measurements. Whenever possible, we average multiple field measurements to account for surface roughness and measurement errors. These raw point measurements and other mass-balance related data are included in the larger USGS Benchmark Glacier Project Comprehensive Data Collection, available at https://doi.org/10.5066/P9AGXQSR Preliminary mass balance estimates for the current calendar year are provided, but do not include direct measurements of ablation after the date of the fall visit. Preliminary estimates of mass balance model this winter ablation for the current year. During subsequent field visits in the following calendar year, any ablation that occurred over the winter season is measured and used to revise the previously modeled estimate of mass balance.

Since the late 1950s, the USGS has maintained a long-term glacier mass-balance program at three North American glaciers. Measurements began on South Cascade Glacier, WA in 1958, expanding to Gulkana and Wolverine glaciers, AK in 1966, and later Sperry Glacier, MT in 2005. Additional measurements have been made on Lemon Creek Glacier, AK to compliment data collected by the Juneau Icefield Research Program (JIRP; Pelto and others, 2013). Direct field measurements are combined with weather data and imagery analyses to estimate the seasonal and annual mass balance at each glacier in both a conventional and reference surface format (Cogley and others, 2011). The analysis framework (O'Neel and others, 2019, van Beusekom and others, 2010) is identical at each glacier to enable cross-comparison between output time series. Vocabulary used follows Cogley and others (2011) Glossary of Glacier Mass Balance. This portion of the data release includes geodetic data used in mass balance analyses. The USGS uses geodetic data to quantify glacier area, glacier hypsometry, and the change in glacier volume and mass (e.g., Cogley and others 2011; Zemp and others 2013; van Beusekom and others, 2010; O'Neel and others 2014). Here we describe these basin-scale data, how they are produced, and the format in which they are preserved and disseminated. Gridded products comprise the first class of data and include orthorectified images and Digital Elevation Models (DEMs). Prior to the early 2000s, these grids were derived from aerial stereo photography or historic topographic maps. More recently, high-resolution space-borne imagery facilitated DEM and ortho-image production using approaches described herein. The second class of data are vector geospatial files of glacier margins. These are interpreted products, produced via manual digitization of the boundary between rock and ice identified from ortho-rectified images, or the boundary between neighboring glaciers identified from ice divide velocity maps. The third class of data are point data from GNSS surveys. These include post-processed points that represent mass balance stake locations, glacier surface elevations, installations, and points of interest on and around these glaciers.