The data here are large wood and geomorphic characteristic data collected in the Summer of 2022 in the Frying Pan River Basin in the Central Mountains of Central Colorado, avalanche report data collected from the Colorado Avalanche Information Center website (avalanche.state.co.us), topographic and vegetation summary data derived from USGS Elevation Products (apps.nationalmap.gov/downloader/) and LANDFIRE (landfire.gov), and data derived from a meta-analysis of the large wood literature. Data were collected to examine research questions related to in-stream wood load volumes supplied by snow avalanches and the resultant geomorphic impacts.

There are nine datasets here. Below we detail the data formatting specifics for each file. Note that data in each file are formatted in "long" format for easy use with statistical software. NAs in all datasets mean that the measure in question was inapplicable to the parameter under consideration.

Description of the data and file structure

Note: Variable explanations below follow the formatting convention of variable name: explanation

In the file stream_characteristics.csv

General geomorphic and watershed characteristics of the stream reaches surveyed. Columns are as follows:

• River: Study catchments (SFFP = South Fork Frying Pan, MC = Marten Creek, MFFP = Main Fork Frying Pan)
• Site: Surveyed reach in each watershed with site number and type (avalanche or control)
• stream_length_m: Length of the surveyed reach in meters
• stream_gradient: Gradient (slope) of the stream through a given study reach (in m/m)
• stream_elevation_m: Elevation above sea level at the downstream end of a given reach (meters)
• drainage_area_km2: Contributing drainage area as calculated at the downstream end of a given reach (via USGS StreamStats, https://streamstats.usgs.gov/ss/) (sq. km)
• mean_bfw_m: Mean bankfull width as measured in a given study reach (meters)
• damaged_forest_area_ha: Forest area damaged or destroyed by a given avalanche (hectares)
• mean_pct_fines: The percentage of the surface bed sediment composed of fines (here defined as sand-sized or smaller sediment) as estimated via visual inspection (unitless)
• ripar_veg: the dominant riparian vegetation as esimated via a visual estimation of prevalence by area (unitless)
• latitude: Latitude for the downstream point of the study reach (Projection: WGS1984)
• longitude: Longitudge for the downstream point of the study reach (Projection: WGS1984)

In the file wood_volume_summary.csv

Summarized data of the wood volumes within each surveyed reach. Columns are as follows:

• River: Study catchments (SFFP = South Fork Frying Pan, MC = Marten Creek, MFFP = (Main Fork) Frying Pan)
• Site: Surveyed reach in each watershed with site number and type (avalanche or control)
• total_wood_volume: total wood volume as calculated by summing the volumes of jams and individual pieces for each reach (in m3)
• total_wood_load_m3_per_100m: Total wood volume normalized by reach length and then multiplied by 100 (in m3/100 m)
• total_wood_load_m3_per_ha: Total wood volume normalized by the area of the stream surface. Stream surface area calculated by multiplying the length of the reach and then multiplying by mean bankfull width (in m3/ha)
• fraction_volume_jams: the fraction of the total wood volume per reach contained in log jams (unitless)
• fraction_volume_pieces: the fraction of the total wood volume per reach that occurs as indiviudal wood pieces (unitless)
• fraction_geomorph_impact: the fraction of the total wood observed that has a geomorphic impact (as defined in the text) (unitless)

In the files jams_and_pieces_avy.csv & jams_and_pieces_control.csv

The unprocessed raw data for all wood jams and individual pieces surveyed. These data include several wood jam and individual piece properties: length, width, depth, and porosity of the former, and length and diameter of the latter. These data also indicate several other wood characteristics, such as piece orientation, stability and decay class, and the presence of a rootwad. Finally, these data include information about the geomorphic impact of each surveyed piece and jam. Columns are as follows:

• Metric: Whether it is an avy reach (avy_wood) or control reach (cp_wood)
• River: Study catchments (SFFP = South Fork Frying Pan, MC = Marten Creek, MFFP = (Main Fork Frying Pan)
• Site: Numbered avalanche or control reach within a catchment
• #: Number of the piece or jam number within a reach
• Length_m: Length of jam or piece (in meters)
• Width_m: Width of jam (in meters)
• Depth_m: Vertical height of jam (in meters)
• Porosity: Jam porosity (%)
• Diameter_cm: Diameter of piece (in centimeters)
• Orientation: Orientation of piece or jaw to flow (prl = parallel, trv = transverse, prp = perpendicular)
• TB: Logistic value (Y/N) for whether a given piece or jam is touching the stream bed
• RW: Logistic value (Y/N) for whether a given piece or jam contains a rootwad
• Pool: Logistic value (Y/N) for whether a given piece or jam is forming a pool
• LSP: Logistic value (Y/N) for whether a given piece or jam is forming a logstep
• Stability: How the jam or piece is anchored (jam = jam with no other clear anchoring, bldr = pinned on boulder, brdg = bridged across channel, rmp = ramped (one end touching bed other touching the bank), bnk = pinned on bank, pin_wd = pinned on other wood (another jam, perhaps))
• Decay: Decay class (brk = bark present, brnch = branches (and bark) present, nb = no bark, rtn = rotten). Combinations of classes (e.g., brnch_brk) indicate multiple classes are contained within a jam
• Function: Geomorphic function of the wood beyond the classes above (ss = storing sediment, vd = creating a vertical drop for the flow, mlti = creating multithread reach, fd = deflecting flow, bnkstb = stabilizing/protecting the stream bank)
• Jam: Logistic (Y/N) as for whether it is a jam
• Volume_m3: Volume of the piece or jam in m3
• type: jam or individual piece

In the file caic_field_reports.csv

Information from reports submitted to the Colorado Avalanche Information Center in the first half of March 2019 for the region in which the study area is located. Data are the type of avalanches observed and other information necessary to access the original copy of each report.

• report_date: Date the report was filed to the Colorado Avalanche Information Center (CAIC)
• observer: The person/organization who filed the report (CAIC - Colorado Avalanche Information Center staff member; Public - member of the general public; Colorado DNR - Colorado Department of Natural Resources staff member; CMC - Colorado Mountain College staff member)
• avalanche_type: The type of avalanche failure observed (SS - Soft slab; HS - Hard Slab; NtSpc - Type not specified; WS - wet slab; WL - wet loose). For more information on the meaning behind these terms, see here: https://avalanche.ca/glossary
• report_approx_location_lat_long: Coordinates (lat,long in decimal degrees) of the approximate location the report refers to. Note that observers sometimes do not reliably indicate avalanche location, but instead use this to denote the location of a trailhead, a distal observation point, etc.
• url: The url for the report

In the file pathway_topo_and_veg_characteristics.csv

Topographic & vegetation characteristics of avalanche pathways in study reaches. Canopy cover comes from the Existing Vegetation Cover raster in the Landfire 2016 Dataset (landfire.gov). Planform curvature and slope angle were derived from a 1-m DEM (acquired via (apps.nationalmap.gov/downloader/) using the Curvature and Slope functions in ArcGIS Pro Version 2.8. Median was calculated for each pathway using the Zonal Statistics function in ArcGIS Pro.

• watershed: The watershed in which the pathway is located
• reach: The corresponding study reach for the observed avalanche pathway (SFFP = South Fork Frying Pan, MC = Marten Creek, MFFP = (Main Fork Frying Pan)
• median_plan_curv: The median curvature of the all cells in the avalanche pathway as measured perpendicular to the fall line using a 1-m DEM. A negative value indicates a concave slope, ~zero indicates planar, and greater than zero indicates a convex slope. For more information on how this was derived, see here: https://www.esri.com/arcgis-blog/products/product/imagery/understanding-curvature-rasters/
• median_slope_degree: The median angle (in degrees) of all cells in the avalanche pathway measured using a 1-m DEM.
• median_canopy_cvr_pct: The median canopy cover (in percent) of all cells in the Existing Vegetation Cover raster contained within the avalanche pathway

In the file ref_recruitment_rates_by_mechanism.csv

These are literature-derived rates for recruitment from processes common to mountain watersheds. Columns are as follows:

• recruiment_mechanism: The mechanism of recruitment examined
• rate_m3_ha_yr: The annual recruitment rate as derived for each reach in the corresponding study
• location: The location of the study
• citation: The reference for the derived rate

In the file ref_wood_loads_landslides_debris_flows.csv

These are literature-derived wood loads for reaches that have experienced landslides/debris flows. Columns are as follows:

• wood_load_m3_ha: The derived wood load from the relevant reaches in the corresponding study
• citation: The reference for the derived volume

In the file ref_wood_loads_northern_dry_conifer.csv

These are literature-derived wood loads for unmanaged forests in the equivalent bioclimatic regime (northern dry conifer) as those in the Frying Pan examined in the publication accompanying this repository (Kemper and Scamardo, 2023). Columns are as follows:

• citation: The reference for the derived volume
• wood_load_m3_ha: The derived wood load from the relevant reaches in the corresponding study
• study: A column indicating whether the value is from the literature (Other Studies), an avalanche reach in the present study of Kemper & Scamardo, 2023 (Avalanche), or a control reach in the present study

Sharing/access Information

Links to other publicly accessible locations of the data: See Journal Supplemental Files

Was data derived from another source? No
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