Incision and deposits resulting from outburst flow from the sag pond at the head of the West Salt Creek rock-avalanche deposit, western Colorado

Beginning at about 2:15 am on May 27, 2016, a landslide from the headscarp of the May 25, 2014, West Salt Creek rock-avalanche deposit (White and others, 2015; Coe and others, 2016; Lewis and others, 2023; Coe and others, 2026) moved into a sag pond at the head of the deposit. At about 2:30 am, the landslide caused the sag pond, which already had an elevated water level due to runoff from snowmelt, to spill over and incise the rock-avalanche deposit that impounded the pond. Continued flow and incision resulted in an outburst flow from the pond that lasted until about 12 pm on May 28, 2016 (refer to Figure 1; Baum and others, 2016; Coe and others, 2017).

We visited the site multiple times after the outburst flow in 2016, on May 28, June 22-24, July 5-8, and August 22-26.  During these field visits, we observed debris flow, mud-flow, hyperconcentrated-flow, and slack-water deposits from the outburst flow; defined, described, and mapped the deposits; made measurements of incision; and collected samples for grain-size analyses. Deposits extended down the West Salt Creek and Salt Creek drainages, to the junction of Plateau Creek, a curvilinear distance of about 13 km downstream from the sag pond spillover point. We walked the entirety of the affected area, and used post-flow, Digital Globe imagery (now part of Vantor, https://vantor.com/product/worldview/) acquired on June 5, 2016 as base material to map deposits and incision from the outburst flow at a scale of 1:1,000. We used light detection and ranging (lidar) data collected from July 13-16, 2016 by the Colorado Geological Survey (https://coloradogeologicalsurvey.org/) to spatially rectify and digitize linework and sample locations from our field mapping in a Geographic Information System (GIS). We analyzed the grain-size distribution of samples using manual sieving and a Malvern Mastersizer 3000 Laser Particle Size Analyzer (Malvern Panalytical, 2026).

In this data release, we provide our GIS files, map unit descriptions, photos of deposits and incision, grain-size data, and photos of sample locations. The coordinate system used for GIS data is WGS 1984 UTM zone 13N. Deposits, incision, and other features that we mapped are portrayed in GIS shapefiles (GISData.zip), described in Table 1, and shown in photographs in Figures 2 and 3. Additional photos of outburst-flow deposits and features are given in the MiscellaneousPhotos.zip file. As an example of our mapping, we have provided .pdf and .jpg map files of the upslope-most portion of our map area (Figure 4). Metadata for each shapefile, and a .lyr file for the ArcGIS Pro (ESRI, 2026) Scarp linetype shown in Figure 4, are included in the GISData.zip file. Results from the grain size analyses are contained in the SieveResults and MalvernResults .csv and .xlsx files in the SampleData.zip file. Metadata for the SieveResults and MalvernResults files are available in the SampleData.zip file. Supplemental information about sieve and Malvern laser analyses and results are contained in the DetailsOfSampleAnalyses.xlsx file and in eight .pdf files. There is one .pdf file for each of the eight sheets contained in the DetailsOfSampleAnalyses.xlsx file. Photos of sample locations are contained in the OutburstFlowSamplePhotos.zip file. The locations of all photos of deposits, features, and samples in Figure 2, Figure 3, MiscellaneousPhotos.zip, and OutburstFlowSamplePhotos.zip are shown by a GIS point with attribute data and a brief description of each photo, in the Miscellaneous shapefile. Unless noted otherwise, all photos were taken by the first author of this data release.

The data included in this data release are used in the following interpretive paper, which is currently (July, 2026) being prepared:

Coe, J.A. and others, in preparation, Pond formation, landslides, and outburst flow following emplacement of the 2014 rock-avalanche deposit in the West Salt Creek valley, western Colorado.

Disclaimer: Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

References

Baum, R.L., Coe, J.A., Geiger, J. W., and Bessette-Kirton, E.K., 2016, Outburst flood creates opportunity to look inside the West Salt Creek rock avalanche deposit, Mesa County, Colorado: Geological Society of America Abstracts with Programs, v. 48, no. 7, https://doi.org/10.1130/abs/2016AM-283901.
   
Coe, J.A., Baum, R.L., Allstadt, K.E., Kochevar, B.F., Jr., Schmitt, R.G., Morgan, M.L., White, J.L., Stratton, B.T., Hayashi, T.A., and Kean, J.W., 2016, Rock-avalanche dynamics revealed by large-scale field mapping and seismic signals at a highly mobile avalanche in the West Salt Creek valley, western Colorado: Geosphere, v. 12, no. 2, p. 607–631, https://doi.org/10.1130/GES01265.1.

Coe, J.A., Bessette-Kirton, E.K., Baum, R.L., Smith, J.B., Schmitt, R.G. and Geiger, J.W., 2017, The West Salt Creek rock avalanche, sag pond, and outburst flood: morphological and sedimentological signatures from a series of extraordinary events: Geological Society of America Abstracts with Programs, v. 49, no. 6, https://doi.org/10.1130/abs/2017AM-306710.   

Coe, J.A., Schmitt, R.G., Hoch, O.J., Smith, J.B., Martinez, S.N., Geiger, J., Jacobson, H.L., 2026, Global Positioning System survey data from 2014-2022 on the West Salt Creek rock avalanche deposit, Mesa County, Colorado: U.S. Geological Survey data release, https://doi.org/10.5066/P14AMPNY.

ESRI, 2026, ArcGIS Pro software, https://www.esri.com/en-us/arcgis/products/arcgis-pro/overview.
 
Lewis, A.C., Baum, R.L., and Coe, J.A., 2023, Distribution of large boulders on the deposit of the West Salt Creek rock avalanche, western Colorado: U.S. Geological Survey Data Report 1178, 6 p., https://doi.org/10.3133/dr1178.

Malvern Panalytical, 2026, Mastersizer 3000, https://www.malvernpanalytical.com. 

White, J.L., Morgan, M.L., and Berry, K.A., 2015, The West Salt Creek Landslide: a catastrophic rockslide and rock/debris avalanche in Mesa County: Colorado Geological Survey Bulletin 55, https://doi.org/10.58783/cgs.b55.isrw2611.