Frying Pan avalanche data

The data here are large wood data collected in the Summer of 2022 in the Frying Pan River Basin in the Sawatch Mountains of Central Colorado. There are six datasets included or referenced here. The first is general geomorphic and watershed characteristics of the stream reaches surveyed.  The second is data from field reports to the CAIC. The third is topographic data for the studied avalanche pathways. The fourth is summary data of the wood volumes within each surveyed reach. The fifth is the unprocessed raw data for all wood jams and individual pieces surveyed. The sixth is a table of literature-derived annual recruitment rates for mechanisms common to mountain streams. Data may also be accessed via the Dryad data repository as linked in the data accessibility statement.

Raw data relate several wood jam and individual piece properties, including length, width, and depth of the former, and length and diameter of the latter. Data also indicate several other wood characteristics, such as piece orientation, stability and decay class, and the presence of a rootwad. Finally, data include information about the geomorphic impact of each surveyed piece and jam. Data were collected to examine research questions related to in-stream wood load volumes supplied by snow avalanches and the resultant geomorphic impacts. 

Methods
Raw data were collected in the field by two trained observers. Wood loads were measured in the field using a census approach for all wood jams and individual wood pieces within the bankfull channel. Jams were identified as accumulations with three or more contiguous pieces; jam volume was quantified by measuring the length, width, and height of a rectangular prism fit to the dimensions of the jam and visually estimating porosity. Porosity was consistently estimated by two independent observers to minimize systematic bias. For individual wood pieces, diameter and length were measured and then used to compute volume via the formula of a cylinder. All measurements were made for wood at least partially contained within the bankfull channel, which was visually estimated in the field using topography (e.g., slope breaks). For wood pieces or jams that extended laterally beyond the bankfull dimensions, those portions outside were excluded from measurements. Measured wood loads were normalized by stream surface area (in ha) for comparisons between reaches with varied bankfull widths and lengths. These data have not been processed other than the above related volume calculations, which were then summarized across sites and watersheds (which have yielded the wood_volume_summary.csv data also presented here). 

Data regarding topographic and vegetation characteristics of the studied avalanche pathways were obtained via freely available remote datasets. These include a 1-m DEM for the study area available from USGS EarthExplorer (https://earthexplorer.usgs.gov/) and vegetation data from the LANDFIRE program (https://landfire.gov/). Canopy cover comes from the Existing Vegetation Cover raster in the LANDFIRE 2016 dataset. Planform curvature and slope angle were dervied from a 1-m DEM using the Curvature and Slope functions in ArcGIS Pro Version 2.8. Median was calculated for each pathway area using the Zonal Statistics function in ArcGIS Pro. 

Avalanche report data was gathered from Colorado Avalanche Information Center field reports (https://avalanche.state.co.us/observations/view-field-reports), restricting the "area" field to Sawatch and Aspen and the dates from 2019-03-01 to 2019-03-15. 

Literature data were gathered using a publication database/search engine (scholar.google.com) to find relevant sources via keyword sources. Data were then processed using the information in each publication to determine rates in units of m3/ha/yr. 

NAs in all datasets mean that the measure in question was inapplicable to the parameter under consideration.

An open-source R code is provided to re-create data processing and figure creation.