Debris Flow, Precipitation, and Volume Measurements in the Grizzly Creek Burn Perimeter June 2021-September 2022, Glenwood Canyon, Colorado (ver. 1.1, October 2023)

This data release contains data summarizing observations within and adjacent to the Grizzly Creek Fire, which burned from 10 August to 18 December 2020. This monitoring data summarizes precipitation, observations of debris flows, and the volume of sediment eroded during debris flows triggered during the summer monsoonal period in 2021 and 2022.
 
Summary rainfall data 2021 (1a_Storm_matrix_2021_gr1mmhr.csv) are provided in a comma-separated value (CSV) file. These data represent the maximum measured rainfall intensities during the monsoon months of 2021 (June-Sept). The columns in the csv file are: Date (m/dd/yy), Name (11 columns have unique gage names), Max 15 min (the maximum 15-minute rainfall intensity in mm/h for the unique gauge), Maximum Value for All Gages (the maximum rainfall intensity for all of the gauges in units of either mm/h or in/15 min), Peak 15-minute Intensity (in/15 min) (the total inches of rainfall in 15 minutes), Debris Flow (this can be 0 indicating no debris flow response, or 1 indicating a debris flow response). Note that we only display gauges that record data sufficient to produce a 15-minute rainfall intensity. Gauges with longer recording rates (e.g., 1 hour) cannot be used to compute the 15-minute rainfall intensity and are not displayed in this table. A null value (‘n/a’) populates the entries where the rain gauge did not measure a 15-minute rainfall intensity greater than 1 mm/hr. Time series rainfall data from the gauges are provided in the child item: Precipitation Data Grizzly Creek Burn Perimeter.
 
Summary rainfall data 2022 (1b_Storm_matrix_2022_gr1mmhr.csv) are provided in a comma-separated value (CSV) file. These data represent the maximum measured rainfall intensities during the monsoon months of 2022 (June-Sept). The columns in the csv file are: Date (m/dd/yy), Name (7 columns have unique gage names), Max 15 min (the maximum 15-minute rainfall intensity in mm/h), Peak 15-minute Intensity (in/15 min) (the total inches of rainfall in 15 minutes), Debris Flow (this can be 0 indicating no debris flow response, or 1 indicating a debris flow response). Note that we only display gauges that record data sufficient to produce a 15-minute rainfall intensity. Gauges with longer recording rates (e.g., 1 hour) cannot be used to compute the 15-minute rainfall intensity and are not displayed in this table. A null value (‘n/a’) populates the entries where the rain gauge did not measure a 15-minute rainfall intensity greater than 1 mm/hr. Time series rainfall data from the gauges are provided in the child item: Precipitation Data Grizzly Creek Burn Perimeter.
 
Debris Flow Observation data 2021 (2a_All_Verification_2021.csv) are provided in a comma-separated value (CSV) file.  The columns in the csv file are: Year (yyyy), State, Fire Name, Fire_ID (index for the fire developed during the USGS debris flow hazard assessment), Fire_SegID (a specific index assigned by the USGS debris flow hazard assessment to the channel segment that produced the debris flow), Site Name (the name of the nearest milemarker on interstate 70), ObservationDate_mmddyyyy, ObservationLatitude_DD, ObservationLongitude_DD, DebrisFlowResponse (this can be 0 indicating no debris flow response, or 1 indicating a debris flow response), SourceOfObservation (name of the observer), StormDate_mmddyyyy, GaugeName, GaugeLatitude_DD, GaugeLongitude_DD, GaugeDist_km (distance from watershed of the debris flow observation to the nearest rain gage in km), StormAccum_mm (the total rainfall during a storm in millimeters), StormDuration_hr (the total duration of a storm in hours), Peak_I15_mm/h (the maximum 15 minute rainfall intensity in mm/h), Peak_I15_in/15min (the total inches of rainfall in 15 minutes), Peak_I30_mm/h (the maximum 30 minute rainfall intensity in mm/h), Peak_I30_in/30min (the total inches of rainfall in 30 minutes), Peak_I60_mm/h (the maximum 60 minute rainfall intensity in mm/h), Peak_I60_in/60min (the total inches of rainfall in 60 minutes). In the event that no rain gage within 6.1 km of an observation measured a 15-minute rainfall intensity greater than 1 mm/hr, no rain gage information is displayed.  
 
Debris Flow Observation data 2022 (2b_All_Verification_2022.csv) are provided in a comma-separated value (CSV) file.  The columns in the csv file are: Year (yyyy), State, Fire Name, Fire_ID (index for the fire developed during the USGS debris flow hazard assessment), Fire_SegID (a specific index assigned by the USGS debris flow hazard assessment to the channel segment that produced the debris flow), Site Name (the name of the nearest milemarker on interstate 70), ObservationDate_mmddyyyy, ObservationLatitude_DD, ObservationLongitude_DD, DebrisFlowResponse (this can be 0 indicating no debris flow response, or 1 indicating a debris flow response), SourceOfObservation (name of the observer), StormDate_mmddyyyy, GaugeName, GaugeLatitude_DD, GaugeLongitude_DD, GaugeDist_km (distance from watershed of the debris flow observation to the nearest rain gage), StormAccum_mm (the total rainfall during a storm in millimeters), StormDuration_hr (the total duration of a storm in hours), Peak_I15_mm/h (the maximum 15 minute rainfall intensity in mm/h), Peak_I15_in/15min (the total inches of rainfall in 15 minutes), Peak_I30_mm/h (the maximum 30 minute rainfall intensity in mm/h), Peak_I30_in/30min (total inches of rainfall in 30 minutes), Peak_I60_mm/h (the maximum 60 minute rainfall intensity in mm/h), Peak_I60_in/60min (the total inches of rainfall in 60 minutes). In the event that no rain gage within 6.1 km of an observation measured a 15-minute rainfall intensity greater than 1 mm/hr, no rain gage information is displayed. 
 
Lidar Derived Volume data (3_Glenwood_Volume_table_final.csv) are provided in a comma-separated value (CSV) file.  The columns in the csv file are: Site Name (the name of the nearest milemarker on interstate 70), Debris Flow Observation Date (mm/dd/yy), Digitized Channel Area (m^2) (the area of a polygon delineating the channel contributing sediment), Net Channel Volume (m^3) (the net volume of erosion (negative values) and deposition (positive values) within the digitized channel area), Net Depositional Fan Volume (m^3) (the net volume of erosion (negative values) and deposition (positive values) within the digitized depositional fan), Upstream Drainage Area at Erosion/Deposition Transition (m^2) (the drainage area where channels switch from primarily erosional to primarily depositional), Latitude of erosion/deposition transition (Decimal Degrees), Longitude  of erosion/deposition transition (Decimal Degrees), Geographic  Name Reference (This is a geographic name if the location of the channel has a known name). Note that the Latitude and Longitude indicate the most downstream point of the channel areas, where erosion transitions to deposition.  Some debris flows contribute to a single depositional fan, and in those cases the depositional volume represents the full volume of the fan. Sometimes debris flows deposited on a road and were cleaned up, therefore no depositional volume was measured by the lidar and the depositional value is left blank.  Furthermore, the locations are repeated if there was more than one observed debris flow at the same spot, however, the volume does not change because the volume difference could only be calculated between the available lidar flights on 10 June 2016 and 24 August 2021. 
 
Rain Gauge Locations (4_Gauge_Location.csv) are provided in a comma-separated value (CSV) file. The columns in the csv file are: Gauge Name, Latitude (Decimal Degrees), and Longitude (Decimal Degrees). Time series rainfall data from the gauges are provided in the child item: Precipitation Data Grizzly Creek Burn Perimeter. 

Acknowledgements: We gratefully acknowledge the rainfall data obtained from the U.S. Geological Survey Colorado Water Science Center, Colorado Department of Transportation, and the Bureau of Land Management. Lidar data was generously provided by the Colorado Department of Transportation and the U.S. Geological Survey 3DEP program. Adjustments to the 3DEP lidar were provided by the original vendor, Merrick and Company.