Field Report: June 7, 2019
We drilled in a new melt wire at the basin entrance (to continue the ice melt measurements we started last spring), deployed the drone (for DEMs and orthoimages), surveyed the lowest point in the dam (to constrain the maximum water level), and deployed additional air temperature sensors higher up in the basin (to facilitate melt modeling across the entire Suicide Basin watershed).
The lake level has risen by approximately 15 m since our last site visit on 16 May. While we still couldn’t access/survey the waterline, our drone data indicated the water was at 406.5 m, which is close to the water level read from the scale bar in the Nupoint timelapse images (within 1‚Äì2 m).
Comparing Friday’s photo to last year’s photos confirms a water level between 406 and 407 m (next figure). The dates on the photos compared also indicate that the lake level is approximately one week delayed compared to last year.
The lowest point in the dam (and thus the highest possible water level) is currently at 439 m a.s.l. and will keep dropping during the melt season. The low point was at 442 m last year when the lake overtopped the dam.
Based on a DEM from last fall (taken at low water levels), I compiled a lake volume lookup table that provides lake volume estimates for different pre-GLOF and post-GLOF water level combinations:
For reference, last year’s post-GLOF water level is marked in orange color. The current water level can be estimated from the scale in the time-lapse images. This morning, the water level was at approximately 408 m a.s.l.