Read Me file for Satellite-derived Alaskan ice-dammed lake drainage events (1985 - 2020)


This dataset provides the lake location and image dates before/after a drainage event was detected.  

Our study includes ice-dammed lakes > 0.1 km2 within the Randolph Glacier Inventory Region 01 (Alaska and NW Canada).


Methods: 

For each lake, we created a true color time-lapse video in Google Earth Engine using all available Landsat 5 (Thematic Mapper, TM), Landsat 7 (Thematic Mapper Plus, ETM+), Landsat 8 (Operational Land Imager, OLI), and Sentinel-2 (Multi-Spectral Instrument, MSI) imagery with less than 20% cloud cover from May 30 to November 1 of each year, from 1985 to 2020. 

For each image, the lake was manually classified as full, partially full, or drained. A drainage event was considered to have occurred between images when the lake was full in one image and partially or fully drained in the subsequent image, or a change from partially full to drained. We know the drainage occurred between these two images, though not the precise drainage date. In this study, we use the term “drainage event” rather than GLOF as we cannot identify the nature and rate of drainage for any particular event, and the term GLOF implies fast release and catastrophic drainage.

This dataset contains an entry for each of the 1150 drainage events detected. 


Dataset: 

LakeID -- Unique ID for each lake. IDs which start with RGI were identified in Rick et al. (2022), and corresponds to the Randolph Glacier Inventory ID of the associated glacier. IDs which start with "PM" are lakes that were not identified in the Rick et al. (2022) dataset but were identified through the Post and Mayo (1971) dataset. 

DateFull -- Date of the image identified as the last date the lake was full before a drainage event. M/D/YYYY

DateEmpty -- Date of the image identified as the first date the lake was drained after an event. M/D/YYYY

lat -- Latitude of the lake, WGS84

lon -- Longitude of the lake, WGS84



References:

Post, A. & Mayo, L. R. Glacier Dammed Lakes and Outburst Floods in Alaska. Hydrologic Investigations Atlas HA-455, USGS (1971).

Rick, B., McGrath, D., Armstrong, W. & Mccoy, S. W. Dam type and lake location characterize ice-marginal lake area change in Alaska and NW Canada between 1984 and 2019. The Cryosphere 16, 297–314 (2022).