Frying Pan avalanche data
Data files
Nov 22, 2023 version files 75.58 KB
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caic_field_reports.csv
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jams_and_pieces_avy.csv
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jams_and_pieces_control.csv
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pathway_topo_and_veg_characteristics.csv
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README.md
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ref_recruitment_rates_by_mechanism.csv
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ref_wood_loads_landslides_debris_flows.csv
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ref_wood_loads_northern_dry_conifer.csv
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stream_characteristics.csv
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wood_volume_summary.csv
Abstract
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.
README: Frying Pan Avalanche Data
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
If yes, list source(s):
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.
Usage notes
CSV files can be opened by all software.