Supplementary data for "Less extreme and earlier outbursts of ice-dammed lakes since 1900"

This respository contains supplementary and source data for the study for Less extreme and earlier outbursts of ice-dammed lakes since 1900 by Georg Veh and co-authors.

We investigate trends in the peak discharge Q_p, flood volume V₀, timing doy (day of year) and elevation Z of glacier lake outburst floods (GLOFs), and focus on ice-dammed lakes. We use Bayesian hierarchical models, implemented in the package brms in in the statistical programming software R. More information on these data, including detailed scripts to process them, are available at  available at https://github.com/geveh/IceDamFailures, and archived at 10.5281/zenodo.7326865.

We provide the following data:

1 The GLOF database

• glofdatabase_2022_05_30.ods: OpenOffice table with all reported GLOFs. Compiliation as of May 30, 2022
• Parameter_Readme.ods: Readme file describing all parameters (i.e. columns) in glofdatabase_2022_05_30.ods

2 Data on glacier elevation changes

• dh_pergla_cut.7z: zipped csv tables of cumulative elevation change (in m) for glaciers with repeat GLOFs between 2000 and 2019

3 Preprocessed GLOF data as R objects

• all_glofs_tibble.RDS: R-object with a preprocessed table of all reported GLOFs
• all_glofs_qp_tibble.RDS: R-object in table format of lakes with repeat GLOFs and reported peak discharge Q_p
• all_glofs_V0_tibble.RDS: R-object in table format of lakes with repeat GLOFs and reported flood volume V₀
• glofs_ice_with_z.RDS: R-object of first reported GLOF from a given lake and its elevation Z

4 Output from Bayesian hierarchial models

a) Regional models

• qp_models.RDS: R-object with regional quantile regression models of Q_p versus time for the 50th and 90th for 4 time periods
• V0_models.RDS: R-object with regional quantile regression models of V₀ versus time for the 50th and 90th for 4 time periods
• doy_trends_per_region.RDS: R-object with regression models of doy versus time for all dated GLOFs in the six regions
• Z_trends_per_region.RDS: R-object with a hierarchical regression models of elevation Z versus time for dated GLOFs in the six regions between 1900 and 2021
• Regional_glacier_and_melt_volumes.rds: R-object containing the total volume of glacier volume and volume change between 2000 and 2019 in 100-m elevation bins  

b) Local models

• V0_model_median_local.RDS: R-object with regional quantile regression models of median V₀ versus time
• qp_model_median_local.RDS: R-object with local quantile regression models of median Q_p versus time
• doy_trends_per_glacier.RDS: R-object with regression models of doy versus time for lakes with repeat GLOFs
• local_Qp_vs_dhdt_model.RDS: R-Object containing a hierarchical model of local changes in Q_p versus glacier elevation change
• local_V0_vs_dhdt_model.RDS: R-Object containing a hierarchical model of local changes in V₀ versus glacier elevation change

4 GIS Data

• Ice_dammed_lakes_Zenodo.7z: zipped folder containing manually mapped outlines of ice-dammed lakes. 
• Region_extents.7z: zipped folder containing the outlines of the study regions.

5 Figures

• Qp_local.pdf: PDF figure showing temporal trends of median Qp for individual glacier lakes
• V0_local.pdf: PDF figure showing temporal trends of median V0 for individual glacier lakes
• doy_local.pdf: PDF figure showing temporal trends in GLOF timing for individual glacier lakes